The police officer was firm while dealing with the unruly crowd.
Yes firm is an adjective eg. firm booting. Booting is the noun and firm is the adjective
The secretary's for the large firm waited for the phones to ring.
Example sentence - It will take a firm stand to win the debate.
Example sentence for the noun 'firm':I work for an international electronics firm.
When meeting a potential employer for the first time it is a good idea to give him or her a firm handshake.
Brushing your teeth regularly promotes good oral health. This firm promotes from within.
My boss is very firm with his company rules but is cool about it.
I would like to speak with the executive in charge of finances, please. I am seeking an executive position with your firm.
The company president had a dictatorial control over the firm. The principal's dictatorial manner offended many of the teachers in the school.
Your racket
A firm believer in old fashioned courtesy, mis-post deprecated the modern tendency to address new acquaintances by their 1st name.
After discovering that his partner was embezzling from their firm, the man shot the culprit; the fact that his partner was also having sex with the man's wife was incidental.