interest

How to sign: a fixed charge for borrowing money; usually a percentage of the amount borrowed
"how much interest do you pay on your mortgage?";

Categories: fixed charge, fixed cost, fixed costs

Within this category: compound interest, simple interest

interest

How to sign: a sense of concern with and curiosity about someone or something
"an interest in music";

Similiar / Same: involvement

Categories: curiosity, wonder

Within this category: concern, enthusiasm

interest

How to sign: a reason for wanting something done
"for your sake"; "died for the sake of his country"; "in the interest of safety"; "in the common interest";

Similiar / Same: sake

Categories: benefit, welfare

Within this category: behalf

interest

How to sign: a diversion that occupies one's time and thoughts (usually pleasantly)
"sailing is her favorite pastime"; "his main pastime is gambling"; "he counts reading among his interests"; "they criticized the boy for his limited pursuits";

Similiar / Same: pastime, pursuit

Categories: diversion, recreation

Within this category: avocation