{Professing themselves to be wise} (phaskontes einai
sophoi). Sophoi is predicate nominative with einai in
indirect discourse agreeing with phaskontes (old verb, from
ph(886d)i, to say, rare in N.T.) in case and number according to
regular Greek idiom (Robertson, _Grammar_, p. 1038). {Became
vain} (ematai(9374)h(8873)an). Ingressive first aorist passive
indicative of mataio(935c) from mataios (empty). Empty reasonings
as often today. {Became fools} (em(9372)anth(8873)an). Ingressive first
aorist passive of m(9372)ain(935c), to be a fool, old word from m(9372)os,
a fool. An oxymoron or sharp saying, true and one that cuts to
the bone. {For the likeness of an image} (en homoi(936d)ati
eikonos). Both words, "a likeness which consists in an image or
copy" (Lightfoot). See  Php 2:7  for "likeness of men" and  Col
1:15  for "image of God." Paul shows indignant contempt for these
grotesque efforts to present pictures of a deity that had been
lost (Denney). Why is it that heathen images of gods in the form
of men and beasts are so horrible to look upon?