Words related to -able
usable (adj.) late 14c., from Old French usable "available, in use" (14c.), from user (see use (v.)). Not a common word before c. 1840, when probably it was re-formed from use (v.) + -able. Related: Usably.
valuable (adj.) "of great value or price," 1580s, from value (v.) + -able. As a noun, "a valuable thing," from 1775 (in modern use often in plural). Related: Valuably. viable (adj.) 1828, from French viable "capable of life" (1530s), from vie "life" (from Latin vita "life," from PIE root *gwei- "to live") + -able. Originally of newborn infants; generalized sense is first recorded 1848. Related: Viably.