The Collaborative International Dictionary of English v.0.48:
Impark \Im*park"\, v. t. [imp. & p. p. Imparked, p. pr. & vb. n. Imparking.] [Cf. Empark.] To inclose for a park; to sever from a common; hence, to inclose or shut up. [1913 Webster] They . . . impark them [the sheep] within hurdles. --Holland. [1913 Webster]