- The definition of ail is to feel sick or have pain.
An example of ail is for an older person to have poor health.
ail definition by Webster's New World
Origin: Middle English eilen ; from Old English eglian, to afflict with dread, trouble ; from egle, harmful; akin to Gothic agls, infamous, Old Norse agi from source awe
ail definition by American Heritage Dictionary
verb ailed, ail·ing, ails verb, intransitive
Origin: Middle English eilen, from Old English eglian, from egle, troublesome.