Expressions (phrases, clauses, etc.), Adverb (fukushi), Noun which may take the genitive case particle 'no'
win or lose; sink or swim; make or break; all or nothing
Usually written using kana alone
のるかそるかの瀬戸際まできた。The situation has come to the point where we either sink or swim.
Also written 乗るか反るか【のるかそるか】