Small untruth about teetotal Liberal (6)
I believe the answer is:
little
'small' is the definition.
(I know that small can be written as little)
'untruth about teetotal liberal' is the wordplay.
'untruth' becomes 'lie' (lie is a kind of untruth).
'about' is an insertion indicator.
'teetotal' becomes 'tt' (abbreviation).
'liberal' becomes 'l' (abbreviation).
'tt'+'l'='ttl'
'lie' going around 'ttl' is 'LITTLE'.
(Other definitions for little that I've seen before include "` `...... pitchers have big ears' '" , "'...... pitchers have large ears'" , "Of no great size" , "part of Stuart in film?" , "Not big, much or important" .)