Reasonable pattern of behaviour by a liberal (6)
I believe the answer is:
normal
'reasonable' is the definition.
(thesaurus)
'pattern of behaviour by a liberal' is the wordplay.
I cannot quite see how this works, but
'pattern' could be 'norm' (I have seen 'Typical pattern' mean 'norm' so perhaps 'pattern' could also mean 'norm') and 'norm' is found within the answer.
'a' is present in the answer.
'liberal' could be 'l' (abbreviation) and 'l' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for normal that I've seen before include "Ordinary, usual" , "Unexceptional" , "Common" , "Usual, typical, expected" , "Commonplace" .)