Almost delete ages (4)
I believe the answer is:
eras
'ages' is the definition.
(I've seen this before)
'almost delete' is the wordplay.
'almost' means to remove the last letter (almost the whole word is kept).
'delete' becomes 'erase' (synonyms).
'erase' with its last letter taken off is 'ERAS'.
(Other definitions for eras that I've seen before include "typeface" , "Long and distinct periods of history" , "Epochs" , "Periods of time" , "Periods, ages" .)