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"
serving to distinguish or identify a species or group; "the distinguishing mark of the species is its plumage"; "distinctive tribal tattoos"; "we were asked to describe any identifying marks or distinguishing features"