Future, present and past (6)
I believe the answer is:
tenses
'future present and past' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tenses that I've seen before include "Tightens up" , "Verb forms that indicate time" , "'Past and present, say (6)'" , "Becomes stretched or taut" , "Past, present etc." .)