Grass before husband's promise in court (4)
I believe the answer is:
oath
'promise in court' is the definition.
'oath' can be an answer for 'promise' (thesaurus). I am not sure about the 'in court' bit.
'grass before husband's' is the wordplay.
'grass' becomes 'oat' (I've seen this in other clues**).
'before' is a charade indicator (letters next to each other).
'husband' becomes 'h'.
'oat'+'h'='OATH'
Can you help me to learn more?
(Other definitions for oath that I've seen before include "word intended?" , "Vow or expletive" , "'Profane, or solemn expression (4)'" , "Curse or solemn promise" , "Courtroom promise" .)