1. Deeply or seriously thoughtful
   - brooding, broody, contemplative, meditative, musing, pensive, pondering, reflective

See also: ruminate, thoughtful

• fledgeless
• fledgeling
• fledgling
• flee
• fleece
• fleeceable
• fleecer
• fleecy
• fleer
• fleet
• fleet admiral
• fleet ballistic missile submarine
• Fleet Street
• fleeting
• fleetingly
• fleetingness
• fleetly
• fleetness
• Fleming
• Flemish
• Flemish dialect
• Flemish-speaking
• flense
• flesh
• flesh and blood