Unchecked means growing or spreading with nothing to stop it. Unchecked growth, spread unchecked, unchecked power.
The check here is a restraint rather than an inspection, which is the older sense of the word and the one in checks and balances. It nearly always warns: unchecked power, unchecked inflation, unchecked spread. The other sense — not verified — is common too, as in unchecked figures. Note check, from chess.
1adjectiveuncheckedGrowing or spreading with nothing to stop it.
“If left unchecked, the weeds will take over the whole garden.”
2adjectiveverifiedNot verified.
“Don't publish the article yet; some of the facts are still unchecked.”
unchecked is a quality of being unrestrained.
Also accepted in games: rampant
From un- + checked.
Etymology from Wiktionary, CC BY-SA