Empty little liquid measure accepted by law (5)
I believe the answer is:
legal
'accepted by law' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs sometimes mean the same thing.
'empty little liquid measure' is the wordplay.
'empty' becomes 'E' (abbreviation e.g. on guages).
'little' becomes 'l' (abbreviation for little).
'liquid' indicates anagramming the letters.
'measure' becomes 'gal' (gal is a kind of measure).
'e'+'l'='el'
'el' is an anagram of 'le'.
'le'+'gal'='LEGAL'
Can you help me to learn more?
(Other definitions for legal that I've seen before include "sanctioned" , "Authorized" , "Street - (1978 Dylan album)" , "Allowed by law" , "In accordance with statute" .)