firm up

US /fɜːrm ʌp/

UK /fɜːrm ʌp/

1.

to make something more definite or certain

:

•

We need to firm up the details of the contract.

•

Can you firm up your plans for the weekend?

:

finalize confirm settle establish secure

2.

to make something physically stronger or more solid

:

•

The concrete needs time to firm up before we can build on it.

•

The jelly will firm up in the refrigerator.

:

harden solidify strengthen stiffen thicken

:

firm on the up and up hold/ stand firm up up to come up with follow up