versant

A gadget lover, Alexander is known to roll up his sleeves to become versant with the latest security technologies.

From Reuters ● May 26, 2013

I have heard from mariners and skilful pilots, much versant in the Indian seas, and have seen in their writings, that these seas contain 12,700 islands, inhabited or desert.

From A General History and Collection of Voyages and Travels — Volume 01 Arranged in Systematic Order: Forming a Complete History of the Origin and Progress of Navigation, Discovery, and Commerce, by Sea and Land, from the Earliest Ages to the Present Time by Robert Kerr

Llan means a level place generally, as most of your readers who are versant in those subjects know.

From Notes and Queries, Vol. IV, Number 110, December 6, 1851 A Medium of Inter-communication for Literary Men, Artists, Antiquaries, Genealogists, etc. by Various

The Golfo Dulce region and the Caribbean versant are humid and inhabited by Hyla elaeochroa.

From The Systematics of the Frogs of the Hyla Rubra Group in Middle America by Juan R. león

The latter presently puts forth the jagged spine of black and repulsive plutonic rock, which notes the Sha'b Makhúl, the corresponding versant of the Nakb Abú Sha'r.

From The Land of Midian — Volume 2 by Sir Richard Francis Burton