Take another look: it’s not exactly Air on a G String ? (9)
I believe the answer is:
backtrack
'string ?' is the definition.
The definition and answer can be both to do with motion as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
'take another look it's not exactly air on a g' is the wordplay.
I cannot really understand how this works, but
'take' could be 'r' (abbreviation for 'recipe', Latin for 'take') and 'r' is present in the answer.
'a' is present in the answer.
'g' could be 'k' (synonyms) and 'k' is found in the answer.
'not exactly' could be 'c' (short for 'circa') and 'c' is present in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
The remaining letters 'back' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for backtrack that I've seen before include "Withdraw" , "Return, retract" , "Retrace one's steps" , "Reverse (opinion)" , "Climb down" .)