Here's what rhymes with fastly.
vastly lastly ghastly Words that almost rhyme with fastly
aptly anti valley assay fatty alley ante nasty sadly flatly sally haply shanty auntie sassy exactly happy badly fancy frankly sandy algae amply handy manly rally scanty abbey galley shabby acne ani chassis madly shaggy tally abbe acme hackney savvy adze ashy chatty dally lassie tali vacantly bastardy catty fanny hanky inaptly natty panty patty raspy ratty sappy carry angry candy gladly taxi cadre daddy glassy grassy paddy radii verbally dandy fiancee finale patchy baggy blankly canny flabby flashy lanky nanny waxy bandy brassy catchy classy lackey laddie snappy tabby tacky bani cabbie cabby caddy chancy maxi nappy navvy pansy scraggly straggly taffy tangy wacky unhappy efficacy brandy crafty pantry abstractly blandly clammy craggy granary grandly compactly cranky cranny gantry grandee granny lamprey scratchy trashy drafty draughty palfrey pederasty scraggy scrappy uncanny immeasurably yeomanry miscarry vigilante rectally chimpanzee immutably inefficacy sycophancy angioplasty profligacy abominably communally homeopathy intermarry polyandry osteopathy satisfactory interminably necromancy homoeopathy indisputably