'-oast' is not a suffix*.
However, here are some words that end with -oast
*See Related links below for more information.
Some words that end or with suffix cain: cocain. marocain.
Words with the suffix ance:acceptanceappearancearroganceassistanceclearancecompliancecontinuancedisappearancedistanceeleganceentrancegrievancemaintenanceperformancepredominanceresistancetolerancesubstancetemperanceviligance
biography
Some words with suffix scious: conscious. subconscious. hyperconscious. semiconscious. overconscious. preconscious. unconscious.
untill andStandstillIntertillRedistillRototillDistillInstillStill
Some words that end with the suffix 'fy' are:acidify.amplify.beautify.belfry.calcify.certify.clarify.classify.detoxify.dignify.electrify.emulsify.falsify.fortify.glorify.horrify.identify.intensify.justify.leafy.liquefy.magnify.mystify.notify.nullify.objectify.pacify.purify.qualify.quantify.ratify.rectify.sanctify.solidify.terrify.testify.typify.unify.verify.versify.vilify.vivify.
Some words that end or with suffix cain: cocain. marocain.
Words with the suffix ance:acceptanceappearancearroganceassistanceclearancecompliancecontinuancedisappearancedistanceeleganceentrancegrievancemaintenanceperformancepredominanceresistancetolerancesubstancetemperanceviligance
Some words that end with the suffix "idle" include inflexible, credible, and indivisible.
There are no common English words that end with the suffix "ankle".
analogybaggybiologybuggyclingydingyedgyenergyfoggylethargymangymuggyorgypedagogypiggyprodigypsychologysaggystingystringysynergytangy
Some words that end with the suffix "full" include beautiful, powerful, and careful.
Some words that end with the suffix "iour" include behavior, humor, and flavor.
altitudeattitudeaptitudebeatitudeconcludecrudeeludeexudefortitudegratitudehackitudelatitudelongitudelassitudemultitudesolitude
Some words that end with the suffix "ock" include: Frock Smock Shamrock Haddock
Some words that end with the suffix "thy" include loyalty, honesty, and sympathy.
Words with the suffix - ing:aimingbeingcomingdatingenteringfindinggoinghavinginsistingjumpingkeepingleavingmovingneedingopeningpretendingquittingreadingseeingtryingusingvotingwaiting