Great time, not at the start, the end (4)
I believe the answer is:
last
'the end' is the definition.
(I've seen this before)
'great time not at the start' is the wordplay.
I cannot quite understand how this works, but
'time' could be 't' (abbreviation) and 't' is present in the answer.
The remaining letters 'las' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for last that I've seen before include "Final; keep going" , "It helps cobbler" , "Least likely" , "` `Let the cobbler stick to his ....' '" , "Final; endure" .)