Words related to y-
word-forming element usually meaning "with, together," from Latin com, archaic form of classical Latin cum "together, together with, in combination," from PIE *kom- "beside, near, by, with" (compare Old English ge-, German ge-). The prefix in Latin sometimes was used as an intensive.
Before vowels and aspirates, it is reduced to co-; before -g-, it is assimilated to cog- or con-; before -l-, assimilated to col-; before -r-, assimilated to cor-; before -c-, -d-, -j-, -n-, -q-, -s-, -t-, and -v-, it is assimilated to con-, which was so frequent that it often was used as the normal form.
The notion is "having a corresponding form (body)." The more usual Germanic compound is represented by Old English gelic, from Proto-Germanic *galikam "associated form" (source also of Old Frisian gelik, Dutch gelijk, German gleich, Gothic galeiks, Old Norse glikr). As an adverb, late Old English onlice, gelice.
late Old English gewær "watchful, vigilant," from Proto-Germanic *ga-waraz (source also of Old Saxon giwar, Middle Dutch gheware, Old High German giwar, German gewahr), from *ga-, intensive prefix, + *waraz "wary, cautious," from PIE root *wer- (3) "perceive, watch out for."