Common words that end in "M" include nouns like "team," "dream," and "room," verbs like "form," "claim," and "swim," and adjectives like "warm," "calm," and "firm."
Nouns that end in "M" go from everyday "team," "room," and "storm" to rarer "venom," "column," and "prism," out to exotic "-ism" and "-um" forms like "optimism," "quantum," and "auditorium."