Having beer on one's breath is quite OK! (4)
I believe the answer is:
hale
'one's breath is quite ok' is the definition.
I can't tell whether this defines the answer.
'having beer on' is the wordplay.
'having' becomes 'h' (this might be a standard abbreviation of which I'm unaware).
'beer' becomes 'ale' (type of beer).
'on' means one lot of letters go next to another.
'h'+'ale'='HALE'
Can you help me to learn more?
(Other definitions for hale that I've seen before include "Healthy and robust" , "Sound of body" , "Well" , "Showing vigorous good health" , "Strong and healthy" .)