Laugh about a young man dressing (5,5)
I believe the answer is:
salad cream
'dressing' is the definition.
(I've seen this before)
'laugh about a young man' is the wordplay.
'laugh' becomes 'scream' (scream is a kind of laugh**).
'about' is an insertion indicator.
'young man' becomes 'lad' (I've seen this before).
'a'+'lad'='alad'
'scream' enclosing 'alad' is 'SALAD CREAM'.
(Other definitions for salad cream that I've seen before include "Sauce" , "Dressing like mayonnaise" .)