sēmĭ-sŭpīnus, a, um, adj.,
half bent backwards , half-supine (poet.): jacet in dextrum semisupina latus, Ov. A. A. 3, 788; id. Am. 1, 14, 20: manus, id. H. 10, 10; Mart. 6, 35, 4.
sēmi-supīnus adj., half bent backwards, reclining: iacet in dextrum semisupina latus, O....
An Elementary Latin Dictionary