solvo

Solvo, solvere, solvi, solutum is third conjugation, from se plus luo, "I release". The core idea is untying, and every other sense is a metaphor off it: freeing a prisoner, casting off a ship, discharging a debt, dissolving a substance, breaking a promise.

The commercial sense is the one that surprises people. Pecuniam solvere is to pay money, because you are loosing yourself from an obligation, and that is where English solvent and insolvent come from. Solvere navem, or just solvere with the ship understood, means to set sail. In the church corpus the theological sense dominates: to loose from sin, hence absolvo and absolution. Note that the participle is soluta with u, not v, and that manuscripts write soluere and soluit for solvere and solvit.