Adult with lad dressed at last in rubber? (7)
I believe the answer is:
aladdin
'rubber?' is the definition.
(I've seen this before)
'adult with lad dressed at last in' is the wordplay.
'adult' becomes 'a' (abbreviation).
'with' is a charade indicator (letters next to each other).
'at last' indicates one should take the final letters.
The final letter of 'dressed' is 'd'.
'a'+'lad'+'d'+'in'='ALADDIN'
(Other definitions for aladdin that I've seen before include "Panto lamp owner" , "Lad with a lamp" , "Panto lamp rubber" , "Finder of magic lamp in Arabian tale" , "pantomime role" .)