Related: debt, profit, rent, usury

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1.
the state of wanting to know or learn about something or someone.
"she looked about her with interest"
synonyms:	attentiveness, attention, absorption; More
antonyms:	boredom
a feeling of wanting to know or learn about (something).
"he developed an interest in art"
the quality of exciting curiosity or holding the attention.
"a tale full of interest"
synonyms:	attraction, appeal, fascination, charm, beauty, allure
"places of interest"
antonyms:	repulsion
a subject about which one is concerned or enthusiastic.
"my particular interest is twentieth-century poetry"
synonyms:	hobby, pastime, leisure pursuit, recreation, diversion, amusement; More
2.
money paid regularly at a particular rate for the use of money lent, or for delaying the repayment of a debt.
"the monthly rate of interest"
synonyms:	dividends, profits, returns; a percentage
"her savings earned interest"
3.
the advantage or benefit of a person or group.
"the merger is not contrary to the public interest"
synonyms:	concern, business, affair
"his attorney guarded his interests"
ARCHAIC
the selfish pursuit of one's own welfare; self-interest.
4.
a stake, share, or involvement in an undertaking, especially a financial one.
"holders of voting rights must disclose their interests"
synonyms:	stake, share, claim, investment, stock, equity; More
a legal concern, title, or right in property.
"third parties having an interest in a building"
5.
a group or organization having a specified common concern, especially in politics or business.
"the regulation of national interests in India, Brazil, and Africa"
verb
verb: interest; 3rd person present: interests; past tense: interested; past participle: interested; gerund or present participle: interesting
1.
excite the curiosity or attention of (someone).
"I thought the book might interest Eric"
synonyms:	appeal to, be of interest to, attract, intrigue, fascinate; More
antonyms:	bore
cause someone to undertake or acquire (something).
"efforts were made to interest her in a purchase"
Origin
late Middle English (originally as interess ): from Anglo-Norman French interesse, from Latin interesse ‘differ, be important,’ from inter- ‘between’ + esse ‘be.’ The -t was added partly by association with Old French interest ‘damage, loss,’ apparently from Latin interest ‘it is important.’ The original sense was ‘the possession of a share in or a right to something’; hence sense 4 of the noun. Sense 1 of the noun and the verb arose in the 18th century sense 2 of the noun was influenced by medieval Latin interesse ‘compensation for a debtor's defaulting.’
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