na-adjective, noun which may take the genitive case particle 'no'
inevitable; unavoidable; bound to happen
Describes a situation or outcome that cannot be avoided; often used in formal or written contexts. Not as common as 避けられない in everyday speech.
At this rate, collapse is inevitable.
It is inevitable that delays in reform will cause chaos.
brinkmate; inevitable checkmate
Shogi term: a position where a checkmate sequence is unavoidable regardless of the opponent's moves. Compare with 必死 (desperate situation in shogi).
See also: 必死
This position is already in brinkmate.
In this recession, it's inevitable that more companies will go bankrupt.
The prime minister's resignation has become inevitable.
必然 is the more abstract, philosophical term for logical inevitability, while 必至 is a more everyday word meaning an outcome is 'certain to happen' given the current trend.
必至 is a more journalistic/colloquial way to say something is certain to happen, while 必然的 has a more formal, logical/analytical flavor.
必死 (same pronunciation) means 'frantic' or 'desperate' in general use and 'desperate defensive position' in shogi, whereas 必至 means an unavoidable outcome or an inevitable checkmate.
必至 means 'inevitable' or 'certain to happen,' whereas 必須 means 'essential' or 'mandatory'; the two are easily confused because of their similar sound and kanji.
From 必 (certainly) + 至 (arrive). The shogi sense is a specialized use of the same characters.