fitting closely against the body or surrounding surface; not loose
Her new jeans were so tight she could barely breathe.
The swimmer pulled on a tight cap to keep her hair dry.
completely sealed so that no air can get in or out
To keep the cookies fresh, she stored them in an airtight glass jar.
The submarine's hull must remain airtight while deep under the ocean.
✦ From air + tight, first recorded in the early 19th century to describe containers that kept food from spoiling.
so perfect, complete, or well-thought-out that no fault, error, or weak point can be found
The lawyer presented an airtight case that convinced the jury.
Before launching the product, the company wanted an airtight marketing plan.
✦ Extended figurative use from the literal sense, first appearing in the early 20th century to describe legal and logical arguments that were as impossible to “leak” faults as a sealed container is to leak air.
