Crossword Genius

A New Testament insect (3)

Ross

I believe the answer is:

'insect' is the definition.
(ant is a kind of insect)

'a new testament' is the wordplay.
'new testament' becomes 'nt'.
'a'+'nt'='ANT'

(Other definitions for ant that I've seen before include "A soldier, for one", "Proverbially hard-working insect", "Emmet or pismire", "one living in colonies", "Small busy insect".)