Words that rhyme with "past":

1 syllable:

ast, bast, blast, cast, caste, classed, fast, gassed, gast, ghast, glassed, grassed, hast, kast, last, massed, mast, nast, rast, vast

2 syllables:

aghast, amassed, avast, contrast, dismast, harassed, lambaste, miscast, outlast, precast, recast

3 syllables:

overmast