From bradus; to delay -- be slack, tarry.
see GREEK bradus
1. rarely transitive, to render slow, retard: τήν σωτηρίαν, the Sept. Isaiah 46:13; passive ὁδός, Sophocles El. 1501 (cf. O. C. 1628). Mostly
2. intransitive, "to be long, to tarry, loiter (so from Aeschylus down): 1 Timothy 3:15; unusually, with the genitive of the thing which one delays to effect, 2 Peter 3:9 τῆς ἐπαγγελίας (A. V. is not slack concerning his promise) i. e. to fulfil his promise; cf. Winer's Grammar, § 30, 6 b. (Sir. 32:22 (Sir. 35:22.)