Formal or literary adjective describing something that is fully intact, without defect, or in its entirety. Often used in elevated or written language.
無事 is the standard word for 'safe' or 'unharmed'; 全い in sense 2 is a formal/literary synonym.
Etymology
Derived from the classical adjective 全し (またし), with the modern form 全い (まったい) arising from sound shift. The kanji 全 carries the meaning of 'whole' or 'complete'.