This will hold the powder firm and close (7)
I believe the answer is:
compact
'close' is the definition.
(I've seen this before)
'this will hold the powder firm' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'firm' could be 'co' (abbreviation for company) and 'co' is found in the answer.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for compact that I've seen before include "Dense; agreement" , "Close - agreement - make-up case" , "Tightly grouped" , "it could be in the bag" , "Small case for face-powder" .)