Greek word usage query

[Anthony Appleyard]

A while ago I wrote some Greek Homeric-type poetry, called "Arateia Notia", about the stars as seen in Australia (as I saw them there in June-July 1984). Many of the constellations seen there are not much like the people and objects that they are named after, so sometimes I used these words with these meanings:-

ἀειδής :: "not resembling", "unlike"
οὒκ εἰδής :: "not resembling", "unlike"
οὒ μάλα εἰδής :: "not much resembling"

Are these word usages correct?

[cramberepetita]

You can't assume that in words beginning with alpha privativum, you can just remove the ἀ(ν)- and be left with an existing word signifying the exact opposite. Sometimes, sure, but far from always (and even if the remaining word exists, look up the meaning to be certain).
Sometimes the truncated word won't exist, because the negative adjective has been created not by prefixing a positive one, but by building on the stem of another type of word. In this case: there is no opposite adjective εἰδής; the negative ἀειδής is built on the noun τὸ εἶδος 'appearance, form', from the Indo-European root *weid-, which also appears in εἶδον (aor. of ὁράω), οἶδα, Lat. video, etc.