n. 1 the act or an instance of losing; the state of being lost. 2 a person, thing, or amount lost. 3 the detriment or disadvantage resulting from losing (that is no great loss). at a loss (sold etc.) for less than was paid for it. be at a loss be puzzled or uncertain. be at a loss for words not know what to say. loss adjuster an insurance agent who assesses the amount of compensation arising from a loss. loss-leader an item sold at a loss to attract customers.
[ ME los, loss prob. back-form. f. lost, past part. of LOSE ]