Ir·rig'u·ous adjective [ Latin irriguus . See Irrigate .] 1. Watered; watery; moist; dewy. [ Obsolete] « The flowery lap Of some irriguous valley spreads her store.» Milton. 2. Gently penetrating or pervading. [ Obsolete] J. Philips.... Found on http://www.encyclo.co.uk/webster/I/99