Both a noun for an enemy/adversary and an adjective meaning 'narrow, tight, distressed.' Distress is literally being in a 'tight spot.' Psalms of lament frequently cry out from tsar.
The Psalms use tsar constantly for enemies and personal distress. The call 'from the narrow place I cried to the LORD' (Ps 118:5) uses this root. God saves from the tsar.
The tightness/narrowness of tsar creates a spatial metaphor for trouble — you're hemmed in with no room to move. God's salvation is spaciousness (Ps 18:19: 'he brought me out into a broad place').