noun-modifying (irregular)
Prenominal modifier meaning 'that is to come' or 'expected in the near future'. Often used in formal or written contexts to refer to upcoming events, eras, or people.
来るべき選挙に備えて準備を進めている。
We are making preparations for the coming election.
We need policies that anticipate the coming changes of the era.
Variant spelling with 来たる; slightly more formal or emphatic, but interchangeable in practice.
From the classical attributive form 来る (きたる) of the verb 来 (く) 'to come', combined with the auxiliary べき (beki) indicating expectation or obligation. The form 来たるべき explicitly includes the okurigana たる.