1. phrasal verb
This treatment helps tone the body, firm up muscles and tighten the skin.
I now go swimming five times a week, which helps firm me up.
The mixture will seem too wet at this stage, but it will firm up when chilled.
2. phrasal verb
If you firm
or if it firms up
, it becomes clearer, stronger
, or more definite
Looking to the future, the Government will firm up their plans for a cleaner, greener,
The ground rules have been firmed up.
At least the bank situation had firmed up.
3. phrasal verb firm
OPEC has agreed to freeze its global oil production slightly in order to firm up crude
COBUILD Advanced English Dictionary. Copyright © HarperCollins Publishers