WordNet (r) 3.0 (2006):

slather
    v 1: spread thickly; "I can't eat bagels without slathering them
         with cream cheese"

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "slather":
   bedaub, besmear, blow, butter, coat, dab, daub, dissipate, enamel,
   gamble away, gild, gloss, go through, gobs, hang the expense, heap,
   lacquer, lavish, lay on, loads, million, oodles, prime, quantities,
   run through, scatter, seize the day, slap on, smear, smear on,
   sow broadcast, spread on, spread with, squander, tar, throw away,
   throw money around, undercoat, wads