Irritable teetotaller Raymond outside (5)
I believe the answer is:
ratty
'irritable' is the definition.
(I've seen this before)
'teetotaller raymond outside' is the wordplay.
'teetotaller' becomes 'tt' (abbreviation).
'raymond' becomes 'ray' (Ray is short for Raymond).
'outside' is an insertion indicator.
'tt' placed within 'ray' is 'RATTY'.
(Other definitions for ratty that I've seen before include "character on the river bank" , "describing vermin" , "with pests" , "Waspish" , "infestation of vermin" .)