firm-v; 2 Senses

Sense Number 1: make or become taut or not loose

Commentary:
NOTE: Usually concrete or physical usages

Examples:
The Jell-O never firmed up, even when bordered by beautiful lettuce.
Like other muscles they can be firmed up by exercise.
The loose teeth had firmed, the gums have a pink, healthy color.

Mappings:
VerbNet: other_cos-45.4
FrameNet: NP
PropBank: firm.01,firm.02
WordNet 3.0 Sense Numbers: 1, 2

Sense Number 2: stabilize, make or become more stronger, more solid

Commentary:
NOTE: Usually abstract or metaphorical usages

Examples:
We have firmed up plans of entering power and energy industries.
The challenge has only firmed up her resolve.
So I lied about the beanpot schedule; it never really firmed up, and I am slow to update.

Mappings:
VerbNet: NM
FrameNet: NP
PropBank: firm.01,firm.02
WordNet Verb Particle Constructions, Multiword Expressions:
firm_up 1