Is in good time but nearly loses a point (5)
I believe the answer is:
early
'is in good time' is the definition.
(being early is arriving in good time)
'nearly loses a point' is the wordplay.
'loses' suggests deleting specific letters.
'a point' becomes 'n' (N is an example).
'nearly' with 'n' removed is 'EARLY'.
'but' acts as a link.
(Other definitions for early that I've seen before include "Infancy, when Wordsworth had 5 across of 5 down" , "Forward" , "Before due time" , "Premature" , "in the morning?" .)