This seems to be a perfect active, third person singular; perhaps from an otherwise unattested verb e)nti/nw, or perhaps a misspelling of e)nte/thke from e)nth/kw (see epsilon 1464).
[1] Adler reports that a superscript comment in ms.V adds one: a)nti\ tou= a)pe/dwke, 'meaning [he/she/it] gave back'.