Brewer's: Carpet Knight
One dubbed at Court by favour, not having won his spurs by military service in the field. Mayors, lawyers, and other civilians knighted as they kneel on a carpet before their sovereign. “Knights of the Carpet,” “Knights of the Green Cloth,” “Knights of Carpetry.”
“The subordinate commands fell to young patricians, carpet-knights, who went on campaigns with their families and slaves.” —Froude: Caesar, chap. iv. p. 91.