Entertaining - before a Liberal becomes dismal (8)
I believe the answer is:
funereal
'dismal' is the definition.
(thesaurus)
'entertaining before a liberal' is the wordplay.
'entertaining' becomes 'fun' ('fun' can be similar in meaning to 'entertaining').
'before' becomes 'ere' (usually literary).
'a liberal' becomes 'al' (I've seen this in other clues).
'fun'+'ere'+'al'='FUNEREAL'
'becomes' acts as a link.
(Other definitions for funereal that I've seen before include "Of the ritual of the dead" , "Of sombre character" , "Gloomy" .)