From western + -ly.
westernly (comparative more westernly, superlative most westernly)
- (obsolete) In or towards the west. [16th-19th c.]
- 1624, John Smith, Generall Historie, in Kupperman 1988, p. 145:
- They have many enemies, namely, all their westernly Countries beyond the mountaines, and the heads of the rivers.