1 syllable:
boast, coast, dosed, ghost, host, most, ost, post, roast, toast

2 syllables:
airpost, almost, at most, backmost, bedpost, beef roast, blade roast, crown roast, doorpost, eastmost, endmost, engrossed, foremost, french toast, frontmost, gatepost, glasnost, goalpost, gold coast, guidepost, headmost, hindmost, impost, inmost, king post, lamb roast, lamppost, midmost, northmost, outmost, outpost, pan roast, pork roast, pot roast, queen post, rib roast, riposte, rump roast, sclerosed, seacoast, signpost, southmost, sternmost, sternpost, the most, thrombosed, topmost, upmost, utmost, veal roast, westmost

3 syllables:
aftermost, at the most, bottommost, command post, corner post, diagnosed, easternmost, farthermost, fingerpost, furthermost, hindermost, hitching post, hithermost, holy ghost, innermost, lowermost, melba toast, middlemost, milepost, milquetoast, nethermost, northernmost, orange toast, outermost, parcel post, rearmost, rudderpost, shutting post, southernmost, starting post, swinging post, tempest-tost, trading post, undermost, uppermost, uttermost, westernmost, whipping post, wiener roast, winning post

4 syllables:
barbary coast, cinnamon toast, deaf as a post, first and foremost, ivory coast, standing rib roast, telegraph post

5 syllables:
definitive host, from pillar to post, military post, missionary post, observation post

6 syllables:
intermediate host

12 syllables:
meteorological observation post

2 syllables:
betrothed