Veer (6)
I believe the answer is:
swerve
'veer' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for swerve that I've seen before include "Suddenly deviate from straight course" , "Suddenly go off course" , "try to avoid" , "Suddenly move off course" , "Turn aside from straight course to avoid something (6)" .)