Somewhat overshot terminus, having a higher temperature (6)
I believe the answer is:
hotter
'having a higher temperature' is the definition.
(I've seen this before)
'somewhat overshot terminus' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'HOTTER' is hidden within 'overshot terminus'.
(Other definitions for hotter that I've seen before include "More heated" , "young car thief" , "Having higher temperature" , "less cold maybe" , "More warm" .)