1. Quick and eager
   "an alacritous response to the invitation"

See also: alacrity, fast

• protohistory
• protology
• protomammal
• protomartyr
• proton
• proton accelerator
• proton magnetic resonance
• protonotary
• protoplasm
• protoplasmic
• protoplasmic astrocyte
• protoplast
• protostar
• Prototheria
• prototherian
• prototypal
• prototype
• prototypic
• prototypical
• Protozoa
• protozoal
• protozoal infection
• protozoan
• protozoic
• protozoological