Briefly rhymes with:
chiefly, awfully, beautifully, chiefly, colorfully, diffley, gruffly, hafley, heffley, hefley, medfly, muffley, peffley, powerfully, roughly, safely, safley, schlafly, stampfli, stiffly, wolfley
Briefly sounds like:
barbell, barbella, bearable, bearably, bravely, burble