Blum
Spook names like Blum & Bloom, plus variants like Bloomberg & Blumenthal, likely have nothing to do with blooming or flowers, but may be a homonym pun with Latin velum / Greek belon / Semitic balam for “veil”.
Latin, Greek, Semitic velum, belon = veil, curtain, muzzle
Semitic balam = wrap up, silencer, muzzle
בלם blm balam : fodder-bag, nose-bag, muzzle; to muzzle, restrain — Hebrew (Jastrow)
בלם blm : to muzzle; to silence; to wrap up (?); to be amazed; to be stupefied — Aramaic (CAL)
בלם blm : to hold in, curb; held in, curbed, restrained, stopped, muzzled, checked; compressed; Arabic ’ablama (= he held his tongue, was silent). — Hebrew (Klein)
בלם blm belam : tied, mute; to put meat between bread, wrap up — Hebrew (Jastrow)