A — 1: βραδύνω
(Strong's #1019 — Verb — braduno — brad-oo'-no )

used intransitively signifies "to be slow, to tarry" (bradus, "slow"), said negatively of God, 2—Peter 3:9 , "is (not) slack;" in 1—Timothy 3:15 , translated "(if) I tarry." See TARRY. In the Sept., Genesis 43:10; Deuteronomy 7:10; Isaiah 46:13 .

B — 1: βραδύτης
(Strong's #1022 — Noun Feminine — bradutes — brad-oo'-tace )

"slowness" (akin to A), is rendered "slackness" in 2—Peter 3:9 .