Verbs

(v)plug away, peg away, slog, keep one's nose to the grindstone, keep one's shoulder to the wheelwork doggedly or persistently“She keeps plugging away at her dissertation”
(v)slog, footslog, plod, trudge, pad, trampwalk heavily and firmly, as when weary, or through mud“Mules plodded in a circle around a grindstone”
(v)slug, slog, swigstrike heavily, especially with the fist or a bat“He slugged me so hard that I passed out”