Having no deviations (8)
I believe the answer is:
straight
'having no deviations' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for straight that I've seen before include "Honest - direct" , "Poker hand of 5 consecutive cards" , "Uncurved" , "Respectable" , "Without deviations or curves" .)