Underinflate

Part of speech: verb

Definitions

1. To fill a tyre, ball or other inflatable object with less air or gas than it should contain
2. Supplying too little air to a tyre or similar item so that it becomes soft and under-pressurized
3. Blowing up an inflatable object to a level below the recommended or required pressure

Etymology: "Underinflate" is a plain formation: the prefix "under-", meaning below the proper or expected level, attached to "inflate". The verb "inflate" comes from Latin "inflare", "to blow into", built from "in-" ("into") and "flare" ("to blow"). English took it in the sense of swelling something with air or gas, and that concrete sense of blowing up a tyre, balloon or life jacket remains the core of the word. The prefix does the work here. "Under-" has been productive in English since Old English, and it attaches freely to verbs to mean not enough of the action. So "underinflate" simply describes inflating something to less than the intended pressure, such as a football pumped too softly or a tyre left below its recommended level.

Synonyms: deflate, flatten

Antonyms: inflate, overinflate