What is the origin of skookum?

Skookum “large, powerful, impressive” derives from Chinook Jargon, a pidgin spoken primarily during the 1800s in the Pacific Northwest that still has hundreds of speakers today. A pidgin is a simplified language variety that fuses elements from multiple languages, and Chinook Jargon is primarily based on four sources: English, French, Lower Chinook (a Chinookan language once spoken along the Columbia River), and Nootka (a Wakashan language still spoken along the western coast of Vancouver Island). However, skookum entered Chinook Jargon instead from Lower Chehalis, a Salishan language once spoken in the southwestern coastal area of the Olympic Peninsula; skookum derives from Lower Chehalis skwəkwə́m “ghost, spirit, monster.” Skookum was first recorded in English circa 1830.