Old-fashioned youth centre (3)
I believe the answer is:
out
'old-fashioned' is the definition.
(as opposed to 'in')
'youth centre' is the wordplay.
'centre' means to look at the middle letters.
The central letters of 'youth' are 'OUT'.
(Other definitions for out that I've seen before include "not acceptable" , "Mistaken; unconscious" , "A way to escape" , "Dismissed, in cricket" , "Means of escape" .)