1. At the same time that
   "they were walking home whilst they were discussing the problem"
   - as, when, while 
2. Even though, in spite of the fact that
   "whilst I love you, I cannot marry you"
   - altho [US], although, though, tho', while

Encyclopedia: Whilst

• self-report personality inventory
• self-reproach
• self-reproof
• self-respect
• self-respectful
• self-respecting
• self-restraining
• self-restraint
• self-righteous
• self-righteously
• self-righteousness
• self-rising flour
• self-rule
• self-sacrifice
• self-sacrificing
• self-satisfaction
• self-satisfied
• self-sealing
• self-seeded
• self-seeker
• self-seeking
• self-service
• self-serving
• self-sowed
• self-sown