Positive - if a farm vet moves around one (11)
I believe the answer is:
affirmative
'positive' is the definition.
('affirmative' can be a synonym of 'positive')
'a farm vet moves around one' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
an anagram of 'farm' is 'frma' which is present in the remaining letters.
This explanation may well be incorrect...
'if' is the link.
Can you help me to learn more?
(Other definitions for affirmative that I've seen before include "That's right" , "Yes; agreeing" .)