n. & v.
n. 1 a concern; curiosity (have no interest in fishing). b a quality exciting curiosity or holding the attention (this magazine lacks interest). 2 a subject, hobby, etc., in which one is concerned (his interests are gardening and sport). 3 advantage or profit, esp. when financial (it is in your interest to go; look after your own interests). 4 money paid for the use of money lent, or for not requiring the repayment of a debt. 5 (usu. foll. by in) a a financial stake (in an undertaking etc.). b a legal concern, title, or right (in property). 6 a a party or group having a common interest (the brewing interest). b a principle in which a party or group is concerned. 7 the selfish pursuit of one's own welfare, self-interest.
v.tr. 1 excite the curiosity or attention of (your story interests me greatly). 2 (usu. foll. by in) cause (a person) to take a personal interest or share (can I interest you in a holiday abroad?). 3 (as interested adj.) having a private interest; not impartial or disinterested (an interested party). at interest (of money borrowed) on the condition that interest is payable. declare an (or one's) interest make known one's financial etc. interests in an undertaking before it is discussed. in the interest (or interests) of as something that is advantageous to. lose interest become bored or boring. with interest with increased force etc. (returned the blow with interest). interestedly adv. interestedness n.
[ ME, earlier interesse f. AF f. med.L, alt. app. after OF interest, both f. L interest, 3rd sing. pres. of interesse matter, make a difference (as INTER-, esse be) ]