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

• unluckily
• unluckiness
• unluckinesses
• unlucky
• unluxuriant
• unluxurious
• unmacadamised
• unmacadamized
• unmade
• unmade-up
• unmaidenly
• unmailable
• unmailed
• unmaimed
• unmaintainable
• unmaintained
• unmakable
• unmake
• unmakes
• unmaking
• unmakings
• unmalicious
• unmalleabilities
• unmalleability
• unmalleable