-able/-ible

turns a verb into an adjective meaning capable of, fit to be, or worthy of the action

Spelled -able, -ible · -ābilis/-ibilis 'capable of, fit for'

Latin -ābilis marked capability: washable cloth can be washed, adaptable plans can adapt, and reversible changes can be reversed.

Words built from it

adaptable — able to adjust to new conditions
adapt + -able (capable of)
avoidable — capable of being prevented
avoid + -able (capable of being)
readable — clear or interesting enough to read
read + -able (capable of being)
washable — safe or suitable to wash
wash + -able (capable of being)
defensible — able to be protected or justified
Latin defens- (defend) + -ible (capable of being)
credible — worthy of belief
Latin cred- (believe) + -ible (worthy of being)
reversible — capable of being changed back
Latin revers- (turn back) + -ible (capable of being)

disabled — from dis- + able + -ed; able came from Latin habilis 'fit,' not -able