1. In a way that was not expected
   - out of the blue 
2. Without advance planning
   - by chance, accidentally, circumstantially

See also: unexpected

• permitter
• permittivity
• permutability
• permutable
• permutableness
• permutation
• permute
• Pernambuco
• pernambuco wood
• pernicious
• pernicious anaemia
• pernicious anemia
• perniciously
• perniciousness
• pernickety
• pernio
• Pernis
• Pernis apivorus
• Pernod
• pernyi moth
• Perodicticus
• Perodicticus potto
• Perognathus
• Perognathus flavescens
• Perognathus flavus