adv.
nub
n.
1 projection, protuberance, knob, boss, lump, bump, knop, protrusion, bulge, node, knot; excrescence, swelling, tumescence:
Press the small nub on the side to open the door.
2 essence, core, heart, nucleus, crux, point, gist, pith, kernel, nucleus, meat, (sum and) substance, main issue, gravamen:
Let's get to the nub of the argument.