Dated crazy hot lad
I believe the answer is:
old hat
'dated' is the definition.
(I've seen this before)
'crazy hot lad' is the wordplay.
'crazy' indicates anagramming the letters.
'hot'+'lad'='hotlad'
'hotlad' with letters rearranged gives 'OLD-HAT'.
(Other definitions for old hat that I've seen before include "On the way out" , "Stale - out of date" , "Out of date thing" , "opposite of hot" , "Out of fashion, like ancient headgear" .)