From ruwq; emptiness; figuratively, a worthless thing; adverbially, in vain -- empty, to no purpose, (in) vain (thing), vanity.
see HEBREW ruwq
H7385. riyq
רִיק noun [masculine] emptiness, vanity; — chiefly in adverb phrase לְרִיק Isaiah 46:4; Job 39:16 in vain (of labour without benefit), so ׳לָר Leviticus 26:16, 20 (H), Isaiah 65:23; and as adverb accusative רִיק 30:7; Psalm 73:13, probably also 2:1 (most = empty scheme as רֵיק 2) compare 4:3 (read probably רֵיק); דִיק בְּדֵי Jeremiah 51:58 = Habakkuk 2:13. — Jeremiah 51:34 see רֵיק 1 above