Common Words:
* Almost
* Ghost
* Host
* Lost
* Most
* Post
Less Common Words:
* Apost (archaic word for a male apostle)
* Frost
* Moist
* Roast
Words with "-ost" as part of a larger suffix:
* Acrobat (from the Greek "-bat" meaning "to walk on tiptoes")
* Aghast (from the Old English "-gast" meaning "ghost, spirit")
* Aloft (from the Old English "-loft" meaning "upper part of a house")
* Avast (from the Dutch "-vast" meaning "fast, secure")
* Blast (from the Old English "-blæst" meaning "a strong wind")
* Cast (from the Old English "-cēast" meaning "to throw")
* Fast (from the Old English "-fæst" meaning "firm, secure")
* Ghost (from the Old English "-gæst" meaning "spirit, soul")
* Hast (from the Old English "-hǣst" meaning "haste, speed")
* Last (from the Old English "-læst" meaning "footprint, track")
* Mast (from the Old English "-mæst" meaning "a tall pole")
* Past (from the Old English "-pæs" meaning "gone by, over")
* Vast (from the Old English "-fæst" meaning "firm, secure")
Note: Some words ending with "-ost" are not truly suffixes. For example, "blast" and "cast" are considered base words, and the "-ost" is part of the word's core meaning.
This is not an exhaustive list, but it gives you a good starting point for words ending with "-ost."