Important measures having impact, limiting female work at night (9,5)

'night' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Maybe they are linked in a way I don't understand?

'important measures having impact limiting female work' is the wordplay.
I cannot quite see how this works, but
'measures' could be 'yards' (yard is a kind of measure) and 'yards' is found within the answer.
'female' could be 'f' (common abbreviation) and 'f' is located in the answer.
'impact' could be 'hit' (hitting is a kind of impacting) and 'hit' is found within the remaining letters.
The remaining letters 'grave' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

'at' acts as a link.

Can you help me to learn more?