Substantives from Adjectives
If the adjective expresses a quality essentially human (or animal), the substantive denotes a person (or animate object) : saj-a, -o, wise (person); blind-a, -o, a blind (person or animal); katolik-a, -o, catholic (person). If the adjective expresses a quality essentially non- human, the substantive denotes a thing : acid-a, -o, acid (adjective and noun); rekt-at -o, (a) straight (line); kav-a, -o, hollow (adjective and noun).
If the quality expressed by the adjective is applicable to both animate and inanimate objects, the substantive form in -o can logically stand for either form of abject, and the meaning must be obtained from the context. Where there is likely to be doubt as to the meaning of the substantive (whether person or thing) the ambiguity can be removed by adding -ulo, -ino for persons and -ajo for things. For example : bono, alt-o, perfekt-o may refer to either persons or things that are good, high, perfect, but bon-ulo, alt-ulo, perfekt-ulo can only apply to persons, and bon-ajo, alt-ajo, perfekt-ajo can only denote inanimate objects.
Appendix - Prefixes
anti-: contra-: against, counter, opposing. Used only in a few scientific terms : anti-bakterio, bactericide ; anti-vermo, vermifuge.
Ordinarily the preposition "kontre" is used instead of and in the same sense as anti-: kontre-Juda, (kontre-Yuda*) anti-semitic; kontre-skorbuta, anti-scorbutic. The use of anti- therefore should be confined strictly to cases where the prefix has been definitely approved by the scientific and technical committees.
arki-: arch-, of eminent degree, chief. Used especially in titles : arki- duk(ul)o, archduke; arki-episkopo, archbishop.
bo-: indicates relationship by marriage, as : bo-patrulo, father-in-law; bo-fratino, sister-in-law.
bi-: two-, Used in scientific terms, as : bi-kapa, bicephalous ; bi-loba, bilobate. The numeral "du" can be used to express the same idea: du-kapa, two-headed, bicephalous.
Note : Mono-: quadri-: quinqua-, sexa-. septua-. okto-, nona- are likewise prefixes often used with technical terms.
des-: (as found in the English words : destruct, destroy) denoting the direct opposite of the idea to which it is prefixed, as : des- agreabla, disagreeable; des-charjar, to unload; des-equilibr-igar, to unbalance; des-bel-igar, to disfigure.
Note : For the difference between des- and ne- see note under ne- in the dictionary. It should have been added that in distinction from ne-, which expresses simple negation, sen- expresses the idea of privation or lack, as : sen-denta, without teeth; sen-hara, hairless.
dis-: denotes separation or dispersion; apart, asunder: dis-part-igar, or dis-pec-igar, to dismember; dis-pozar, to dispose, lay out; dis- ruptar, to disrupt; dis-donar, to distribute (promiscuously). Used with verbal roots.
elk*-: e-. electric. As in elk*-letro, e-mail
The Ido "e-" (EH) as a prefix for communications by computer (e-mail), is too short and too inaudible for speech, compared to the sound of the English "e-" (EE). The non-official prefix "elk-" is developing some following among Idists.
ek-: {prep}: out of (motion from; made or extracted from; fractional part of), out from, (US) out (forth from), of (made of); el portis ol ek la chambro - she carried it out of (US: out) the room; irar ek la domo - go out of (US: out) the house; sis ek dek - six out of ten;vazo ek oro - gold vase; ek'irar - to go out, get out, walk out; ek'apareskar - to appear to be, to turn out to be; Ek'apareskabas ke ni lernis en la sama skolo.
ex-: ex-, late, former, retired. Indicates one who formerly held a position : ex-prezidanto, ex-president; ex-oficiro, a former officer.
gala-: gala-. This is properly an adjective but is used in a few instances as the first element of a composed word: gala-festo, gala festival; gala-robe, a gala robe.
ge-: denotes both sexes taken together : ge-patri, father and mother, parents; ge-siori, Mr. and Mrs-, ladies and gentlemen. Note: This prefix is to be used only when it is desired to emphasize the presence ofboth sexes. In direct derivation (simple endings in -ar, -o, -a), substantives in general denote undetermined sex, therefore, simple "patri" translates the idea of parents, and "siori" that ofladies and gentlemen. In modern standard Ido "ge-patri" has been replaced by "genitori".
mi-: half; partly, semi-, demi-, in the sense ofless than is usual, full and normaclass="underline" mi-cirklo, half-circle; ml-horo, half an hour; mi- fratulo, hall-brother; mi-lumo, half-light, twilight; mi-ombre, half-shade, partial shadow; ml-mortinta : half-dead (cf. quaz-a, -e); mi-mond-umo : demi-monde.
neben*-: vice-. Indicates one who would act in the place of an
authentic person in the position in case of emergency. neben*- prezidanto, vice-president, vice-chairman
mis-: denotes erroneous, wrong action; used with verbal roots: mis- komprenar, to misunderstand; mis-pronuncar, to mispronounce; mis-prezentar, to misrepresent; mis-uzo, misuse.
ne-: (adv. used as prefix) not, non-, un-, in-, im-, ir- : ne-savar, to be ignorant of; ne-posibla, impossible ; ne-populara, unpopular; ne- responsiva, irresponsible; (cf. des-).
par-: (used especially with verbal roots) denoting perfection or thorough completion of an action: par-lernar, to learn
thoroughly; par-plugar, to plow thoroughly; par-lektar, to read thoroughly or through to the very end; par-facer, to do thoroughly, to complete; par-irar, to go (through) to the end.
para-: (with substantive roots) denoting protection against, something to ward off: para-fairo, a screen or protection against fire, a fireguard; para-fulmino, some sort of a protection against lightning, a lightning conductor; para-pluvo, a protection against rain, an umbrella; para-vento, a wind-shield.
pre-: pre-, before ; replaces the preposition "ante" in composed words: pre-datizar, to antedate; pre-destinar, to predestine; pre-dicar, to predict; pre-hiere, (on the) day before yesterday ; pre-avino, great-grandmother.
pseudo*-: pseudo, false, counterfeit, as in English. A rarely used prefix.
quadri-: quadri-, quadru-: quad-; four ; used chiefly in scientific words: quadri-latera, quadrilateral; quadri-peda : quadruped.
retro-: (with verbal roots) retro-, backtward, inverse action : retro- agar, to retroact; retro-irar, to go back(ward).
ri-: (with verbal roots) re-, back (to an original or former state or position) again (in the sense of repetition or restoration); ri- elektar, to re-elect; ri-enirar, to re-enter; ri-donar, to give back (again); ri-facar, to do over again, remake; ri-dicar, to say again, repeat.
sen-: -less, without, free from : Indicates absence, lack, privation, destitution sen-kapa, headless; sen-kulpa, guiltless; sen-arma, without arms, weapon-less; sen-denta, toothless;