Old-fashioned and dead wrong about central heating (5)
I believe the answer is:
dated
'old-fashioned' is the definition.
(thesaurus)
'dead wrong about central heating' is the wordplay.
'wrong' indicates anagramming the letters.
'about' is an insertion indicator.
'central' says to take the centre.
The middle letter of 'heating' is 't'.
'dead' with letters rearranged gives 'daed'.
'daed' going around 't' is 'DATED'.
'and' is the link.
(Other definitions for dated that I've seen before include "Old fashioned" , "Unfashionably old" , "Antiquated" , "Met socially by arrangement" , "Passe" .)