| DIFFUSER | • diffuser adj. Comparative form of diffuse: more diffuse. • diffuser n. Any person or thing that diffuses. • diffuser n. A device designed to diffuse a scent efficiently. |
| DIFFUSOR | • diffusor n. Alternative form of diffuser. • DIFFUSOR n. one that diffuses, also DIFFUSER. |
| FRISKFUL | • friskful adj. (Rare) Lively; frolicsome. • FRISKFUL adj. brisk; lively; frolicsome. |
| FUNFAIRS | • funfairs n. Plural of funfair. • FUNFAIR n. an amusement park. |
| FURFAIRS | • FURFAIR n. dandruff, also FURFUR. |
| FUSIFORM | • fusiform adj. (Chiefly botany, zoology) Shaped like a spindle with yarn spun on it; having round or roundish cross-section… • FUSIFORM adj. tapering toward each end. |
| GRUFFISH | • gruffish adj. Somewhat gruff. • GRUFFISH adj. somewhat gruff. |
| RUFFIANS | • ruffians n. Plural of ruffian. • RUFFIAN v. to behave like a tough, lawless person. |
| SIFFLEUR | • SIFFLEUR n. (French) a (male) professional whistler. |
| SNUFFIER | • snuffier adj. Comparative form of snuffy: more snuffy. • SNUFFY adj. soiled with snuff. |
| SQUIFFER | • SQUIFFER n. (slang) a concertina. |
| STUFFIER | • stuffier adj. Comparative form of stuffy: more stuffy. • STUFFY adj. badly ventilated. |
| SUFFARIS | • SUFFARI n. (Swahili) a hunting expedition, also SAFARI. |
| SUFFICER | • sufficer n. A person who aims to be self-sufficient rather than to accumulate further wealth. • SUFFICER n. one who suffices. |
| SURFFISH | • SURFFISH n. a Western American fish, aka surfperch. |