A verb of exuberant, vocal praise — louder than quiet adoration, with connotations of proclaiming loudly and publicly. It also carries the sense of 'stilling' or 'pacifying' — perhaps the paradox that genuine praise quiets and settles the heart even as it bursts outward. Used in Psalms for bold declaration of God's greatness.
Shabach appears in the command-psalms that call worshipers to praise — 'Let everything that has breath praise the LORD' (Ps 150:6 draws on multiple praise verbs). It often appears in Psalms of ascent and enthronement psalms where God's kingship is proclaimed loudly to all nations. To shabach God is to make a public, confident declaration that his greatness is worth shouting about.