Late 16th century; earliest use found in William Kempe (c1560–1601), writer on education. From western + -ly, probably partly as alteration of westerly.
Definition of westernly in US English:
westernly
adverbˈwɛst(ə)nli
1In a western manner.
2Towards or in the west.
Origin
Late 16th century; earliest use found in William Kempe (c1560–1601), writer on education. From western + -ly, probably partly as alteration of westerly.