Latin word intendo comes from Latin ingratus (Thankless. Ungrateful. Unpleasant, disagreeable.), Latin tendere

Detailed word origin of intendo

Dictionary entry	Language	Definition
ingratus	Latin (lat)	Thankless. Ungrateful. Unpleasant, disagreeable.
tendere	Latin (lat)
intendo	Latin (lat)	(Medieval Latin) I obey (+ dative). (New Latin) I understand. I aim, turn, direct.. I intend to. I stretch out, stretch, strain.. I turn my attention to, focus (on).