1. In an imperceptible manner or to an imperceptible degree
   "the power of the Secretary of State in London increased gradually but imperceptibly"
   - unnoticeably

See also: imperceptible

Antonym: perceptibly

• Roswell
• rosy
• rosy boa
• rosy-cheeked
• rosy-colored
• rosy-coloured
• rosy-purple
• rot
• rot-resistant
• rota
• Rotarian
• rotary
• rotary actuator
• Rotary Club
• rotary converter
• rotary engine
• Rotary International
• rotary joint
• rotary motion
• rotary press
• rotary wing
• rotatable
• rotate
• rotated
• rotating mechanism