A fatheaded story, but pleasant (7)
I believe the answer is:
affable
'pleasant' is the definition.
(I've seen this before)
'a fatheaded story' is the wordplay.
'fatheaded' becomes 'f' (this might be a standard abbreviation of which I'm unaware).
'story' becomes 'fable' (fable is a kind of story).
'a'+'f'+'fable'='AFFABLE'
'but' acts as a link.
Can you help me to learn more?
(Other definitions for affable that I've seen before include "Pleasantly friendly" , "Warm and friendly" , "Obliging" , "Pleasant to talk to" , "Showing friendly warmth" .)