ff or ff.

1. Fecerunt (Latin), (they) did it or made it
2. Folios (printing)
3. Following pages, lines, etc
4. Fortissimo (music)

FF

1. Form feed (computing)
2. French franc or francs

• slubbier
• slubbiest
• slubbing
• slubbings
• slubbs
• slubby
• slubs
• sludge
• sludges
• sludgier
• sludgiest
• sludgy
• slue
• slued
• slueing
• slues
• slug
• slug-a-bed
• slugfest
• slugfests
• slug-foot-second
• sluggabed
• sluggard
• sluggardise
• sluggardised