Sober? Stand almost everybody swallowing short! (8)
I believe the answer is:
teetotal
'sober?' is the definition.
('teetotal' can be similar in meaning to 'sober')
'stand almost everybody swallowing short' is the wordplay.
I cannot quite see how this works, but
'stand' could be 'tee' (I've seen this before) and 'tee' is found in the answer.
'short' could be 'tot' (both can mean a small alcoholic drink) and 'tot' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for teetotal that I've seen before include "Pledged to abstain from alcohol" , "temperate" , "Eschewing booze" , "Sober" , "Abstaining completely from alcoholic drinks" .)