Firmest

adjective

1. Steadfast, secure, solid (in position)

   "It's good to have a firm grip when shaking hands."

2. Fixed (in opinion)

   "He was firm that selling his company would a good choice and didn't let anyone talk him out of it."

3. Durable, rigid (material state)

   "firm flesh; firm muscles, firm wood; firm land (i.e. not soft and marshy)"