WordWeb Online

1. (often followed by 'of') a large number, amount or extent
   "a muckle of letters";
   - batch, deal, flock, good deal, great deal, hatful, heap, lot, mass, mess, mickle [archaic], mint, mountain, passel [US], peck, pile, plenty, pot, quite a little, raft, sight, slew, spate, stack, tidy sum, wad, bunch

Derived forms: muckles

Type of: large indefinite amount, large indefinite quantity