Mostly get on well with the fellow offering banality (6)
I believe the answer is:
cliche
'banality' is the definition.
('cliche' can be a synonym of 'banality')
'mostly get on well with the fellow' is the wordplay.
'mostly' means to remove the last letter.
'get on well' becomes 'click'.
'with' means one lot of letters go next to another.
'the fellow' becomes 'he' (I've seen this in other clues).
'click' with its last letter taken away is 'clic'.
'clic'+'he'='CLICHE'
'offering' acts as a link.
(Other definitions for cliche that I've seen before include "Trite or obvious remark" , "Saying become tedious with over-use" , "Nothing new in that, so to speak" , "Chestnut" , "Saying repeated too often" .)