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
an estimation that is too low; an estimate that is less than the true or actual value
make too low an estimate of; "he underestimated the work that went into the renovation"; "Don't underestimate the danger of such a raft trip on this river"