Takes a break after Charlie reaches the top (6)
I believe the answer is:
crests
'reaches the top' is the definition.
(I've seen this in another clue)
'takes a break after charlie' is the wordplay.
'takes a break' becomes 'rests' (resting is a kind of taking a break).
'after' is a charade indicator (letters next to each other).
'charlie' becomes 'C' (phonetic alphabet).
'rests' put after 'c' is 'CRESTS'.
(Other definitions for crests that I've seen before include "Emblems of families" , "summits" , "Topmost ridges of mountains" , "Tufts on birds' heads, or tops of waves" .)