firmest
adjective
Definitions
Steadfast, secure, solid (in position)
Example: It's good to have a firm grip when shaking hands.
Fixed (in opinion)
Example: He was firm that selling his company would a good choice and didn't let anyone talk him out of it.
Durable, rigid (material state)
Example: firm flesh; firm muscles, firm wood; firm land (i.e. not soft and marshy)