Foolish mum almost entirely untruthful about husband's hesitancy (6-9)

'hesitancy' is the definition.
(thesaurus)

'foolish mum almost entirely untruthful about husband's' is the wordplay.
I cannot really understand how this works, but
'mum' could be 'sh' (both can mean to be quiet) and 'sh' is found in the answer.
'entirely' could be 'all' (all can mean entirely or completely) and 'all' is found in the answer.
'husband' could be 'h' (abbreviation) and 'h' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?