superfirm
adjective
su·per·firm ˌsü-pər-ˈfərm 
: extremely firm
superfirm mattresses
Word History
First Known Use
1928, in the meaning defined above
- tight-knit
- tight-laced
- tight-leg
- tight-lipped
- tight-locked
- tight-mouthed
- tighten
- tighten one's belt
- tighten the noose
- tighten the purse strings
- tighten the screws
- tighten the thumbscrews on
- tighten up
- tighten/put the thumbscrews on
- tightened
- tightened up
- tightener
- tighteners
- tightening
- tightening up
- tightenings
- tightens
- tightens up
- tighter
- tightest