Raise a pound with husband's pretentious nonsense (4)
I believe the answer is:
blah
'pretentious nonsense' is the definition.
(I've seen this before)
'raise a pound with husband's' is the wordplay.
'raise' says the letters should be written in reverse.
'pound' becomes 'lb' (abbreviation for the unit of weight).
'with' says to put letters next to each other.
'husband' becomes 'h' (abbreviation).
'a'+'lb'='alb'
'alb' written backwards gives 'bla'.
'bla'+'h'='BLAH'
(Other definitions for blah that I've seen before include "Insipid" , "Meaningless substitute for tedious words" , "Rhubarb" , "bunkum!" , "Dull" .)