To make something more definite, solid, or physically firmer.
To make a plan, deal, or body part stronger and more certain.
3 meanings, ordered from most common to least. Color-coded by CEFR level.
To make a plan, agreement, or arrangement more definite and certain.
"We need to firm up the details of the contract before the meeting on Friday."
We need to firm up our plans for the summit.
— Reuters, diplomatic reporting, commonly attributed phrase in news coverage
To become or make something physically harder or more toned.
"These exercises are designed to firm up your core muscles."
To strengthen a position, relationship, or stance.
"The new trade agreement helped to firm up ties between the two countries."
To make something that is 'firm' go further in that direction — harder, more solid, more set.
To make a plan, deal, or body part stronger and more certain.
Used both literally (muscles, physical objects) and figuratively (plans, agreements, relationships). Common in business and fitness contexts. Slightly more frequent in American English.
Natural word combinations native speakers use most often.
The five tense forms you'll use most often.
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