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"
excite to an abnormal condition, of chafe or inflame; "Aspirin irritates my stomach"
excite to some characteristic action or condition, such as motion, contraction, or nervous impulse, by the application of a stimulus; "irritate the glands of a leaf"