bedridden (adj.)

also bed-ridden, "confined to bed by age, infirmity, or sickness," mid-14c., from late Old English bæddrædæn "bedridden," adjective from bedreda "bedridden (man)," literally "bedrider," from bed + rida "rider" (see ride (v.)). Originally a noun, it became an adjective and acquired an -en on the analogy of past-participle adjectives from strong verbs such as ride.