Lambaste rhymes with:
bast, aghast, amassed, assed, ast, bast, blast, cast, caste, classed, fast, gassed, gast, glassed, grassed, harassed, hast, kast, last, lymphoblast, massed, mast, miscast, nast, passed, past, precast, rast, recast, surpassed, unsurpassed, vast
Lambaste sounds like:
lambasted, lamppost, lymphocyte