not changeable or subject to change; "a fixed and unchangeable part of the germ plasm"-Ashley Montagu; "the unchangeable seasons"; "one of the unchangeable facts of life"
a tool resembling a hammer but with a large head (usually wooden); used to drive wedges or ram down paving stones or for crushing or beating or flattening or smoothing
a light drumstick with a rounded head that is used to strike percussion instruments
a sports implement with a long handle and a head like a hammer; used in sports (polo or croquet) to hit a ball