godan verb (-ru), intransitive verb
pitch forward; fall forward; stumble forward
Describes losing balance and lurching or falling forward, often with a sudden motion. Related to のめる (to fall forward).
See also: のめる
石につまずいて、つんのめりそうになった。
I tripped on a stone and almost pitched forward.
急に止まれなくて、前につんのめってしまった。
I couldn't stop suddenly and ended up stumbling forward.