Miserable chap tucking into toast (9)
I believe the answer is:
cheerless
'miserable' is the definition.
(I've seen this before)
'chap tucking into toast' is the wordplay.
'chap' becomes 'les' ().
'tucking into' means one lot of letters goes inside another.
'toast' becomes 'cheers' (I've seen this before).
'les' inserted inside 'cheers' is 'CHEERLESS'.
(Other definitions for cheerless that I've seen before include "Bleak" , "Gloomy, depressing" , "Miserable" , "not hip?" , "Dreary" .)