1. By chance
   - possibly, perhaps, maybe, mayhap [archaic], peradventure [archaic] 
2. [archaic] Through chance, "To sleep, perchance to dream.."
   - by chance [archaic]

Encyclopedia: Perchance

• unreliable
• unreliableness
• unreliably
• unrelieved
• unremarkable
• unremarkably
• unremarked
• unremedied
• unremitting
• unremittingly
• unremorseful
• unremunerative
• unrenewable
• unrenewed
• unrentable
• unrepaired
• unrepeatable
• unrepentant
• unrepentantly
• unreplaceable
• unreportable
• unreported
• unrepresentative
• unrepressed
• unreproducible