Reckon there's time left inside to be cowardly (7)
I believe the answer is:
gutless
'be cowardly' is the definition.
(I've seen this before)
'reckon there's time left inside' is the wordplay.
'reckon' becomes 'guess' (guessing is a kind of reckoning).
'there's' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'left' becomes 'l' (common abbreviation).
'inside' means one lot of letters goes inside another.
't'+'l' is 'tl'.
'guess' going around 'tl' is 'GUTLESS'.
'to' acts as a link.
(Other definitions for gutless that I've seen before include "lacking a beer belly?" , "Cowardly, lacking intestines" , "Showing no evidence of bottle" , "racket like this is not much use" , "Lacking any backbone" .)