Like a gymnast
I believe the answer is:
spry
'like a gymnast' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for spry that I've seen before include "Nimble, brisk" , "Agile (for one's age?)" , "Alert" , "'Agile, nimble (4)'" , "Lively (especially of an older person)" .)