1. By chance
   "we may possibly run into them at the concert"
   - perchance, perhaps, maybe, mayhap [archaic], peradventure [archaic] 
2. To a degree possible of achievement or by possible means
   "they can't possibly get here in time for the funeral?"

See also: possible

Antonym: impossibly

• functionary
• functioning
• fund
• fund-raising campaign
• fund-raising drive
• fund-raising effort
• fundament
• fundamental
• fundamental analysis
• fundamental frequency
• fundamental interaction
• fundamental law
• fundamental measure
• fundamental particle
• fundamental principle
• fundamental quantity
• fundamentalism
• fundamentalist
• fundamentalistic
• fundamentally
• fundamentals
• fundamentals analysis
• funded
• fundholder
• fundie