Underinflated

Part of speech: adjective

Definitions

1. Having been filled with less air or gas than the recommended amount, leaving it soft or flat
2. Describing a tire, ball or similar object that holds insufficient air pressure to function properly
3. Filled to a pressure lower than what is required, so the object appears soft or sagging

Etymology: "Underinflated" is built from "under-," meaning insufficiently or below the proper amount, and "inflated," the past participle of "inflate." The stem comes from Latin "inflare," "to blow into," formed from "in-" ("into") and "flare" ("to blow"). That Latin root gave English its original sense of swelling something with air or gas, and "inflate" was later extended to describe growth in size, quantity, or value, as with inflated prices. Combining the two elements produces a plain description: something filled with less air, gas, or fluid than it should hold. The pattern is a productive one in English, where "under-" attaches freely to verbs and participles to mean "not enough," so the word needs no special history beyond its parts. Its most familiar use is for tyres, sports balls, and inflatable objects that have lost pressure.

Synonyms: deflated, flat, soft

Antonyms: inflated, overinflated