Have no fellowship with (μη συνκοινωνειτε). No partnership with, present imperative with μη. Followed by associative instrumental case εργοις (works).

Unfruitful (ακαρποις). Same metaphor of verse Ephesians 5:9 applied to darkness (σκοτος).

Reprove (ελεγχετε). Convict by turning the light on the darkness.