The Collaborative International Dictionary of English v.0.48:

Surbate \Sur*bate"\, v. t. [imp. & p. p. Surbated; p. pr. &
   vb. n. Surbating.] [F. solbatu, p. p., bruised (said of a
   horse's foot); sole a sole (of a horse's foot) + battu, p. p.
   of battre to beat.]
   1. To make sore or bruise, as the feet by travel. [Obs.]
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            Lest they their fins should bruise, and surbate sore
            Their tender feet upon the stony ground. --Spenser.
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            Chalky land surbates and spoils oxen's feet.
                                                  --Mortimer.
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   2. To harass; to fatigue. [Obs.] --Clarendon.
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