mentoi is a conjunction that marks a qualifying or contrasting statement in the clauses where it appears.

Across the supplied verses, μέντοι is a conjunction introducing or marking a statement that qualifies, contrasts with, or continues what surrounds it: the APB variously presents such clauses with “Nevertheless,” “however,” “but,” or “yet.”

1. Conjunction marking qualification or contrast · dominant

   The form is tagged as a conjunction in every occurrence. In 2 Timothy 2:19 the APB renders “Nevertheless the strong foundation of God stands”; in John 12:42 it renders “Nevertheless many even of the rulers trusted in him,” followed by their failure to confess. The same connective role is reflected in qualifying or contrasting clauses in James 2:8, John 20:5, John 21:4, John 4:27, John 7:13, and Jude 1:8.

   2 Timothy 2:19James 2:8John 12:42John 20:5John 21:4John 4:27

In the Anselm Project Bible: The APB varies among “Nevertheless,” “however,” “but,” and “yet” in these verses. These English connectives show the clauses' presentation rather than a fixed rendering for the term.