1.AdverbWhile intoxicated or inebriated, in any degree from mildly impaired to stupefied, by a mind-altering substance, typically alcohol; thus, especially, drunk.
"He was arrested for driving under the influence.; He was fired for showing up under the influence."
2.AdjectiveIntoxicated or inebriated, in any degree from mildly impaired to stupefied, by a mind-altering substance, typically alcohol; thus, especially, drunk.
"He was arrested for driving while under the influence.; He was fired for showing up when he was under the influence."