Cocky type later horsing around aboard boat (5,5)
I believe the answer is:
smart aleck
'cocky type' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'later horsing around aboard boat' is the wordplay.
'horsing around' indicates an anagram (I've seen 'horses around' mean this).
'aboard' means one lot of letters goes inside another.
'boat' becomes 'smack' (smack is a kind of sailing vessel).
'later' is an anagram of 'rtale'.
'rtale' put into 'smack' is 'SMART-ALECK'.
Can you help me to learn more?
(Other definitions for smart aleck that I've seen before include "Upstart" , "Know-all" , "Wise guy" .)