TROSMIF

Make words with F

No third-person -S verbs, and

No plural -S words, as always

Missing: MIFF

Merry Christmas!

FIRM FIRST FIST FOIST FOOT FORM FORT FORTISSIMO FROM FROST ISOFORM MISFIT MOTIF RIFF RIFT ROOF ROTIFORM SIFT SOFFIT SOFT STIFF TIFF TRIFORM