Firm up and Shake hands

Firm up verb - To become physically firm or solid.

Shake hands and firm up are semantically related. In some cases you can use "Shake hands" instead a verb "Firm up".

Shake hands verb - Take someone's hands and shake them as a gesture of greeting or congratulation.

Firm up and shake hands are semantically related. Sometimes you can use "Firm up" instead a verb phrase "Shake hands".