a. [TRANS- 3.] Lying, living, or done beyond the frontier of a country.
1877. Ld. Lytton, Lett. (1906), II. xv. 481. The rudest and most unmanageable transfrontier chieftains.
1909. Daily Chron., 22 Jan., 3/4. A personal history of trans-frontier surveys and boundary demarcations.