'Libation' in the Bible

"Oh rebellious children!" {declares} Yahweh, "to make a plan, but not from me, and pour out a libation, but not [from] my Spirit, {so as to add} sin to sin.

“Among the smooth stones of the ravineIs your portion, they are your lot;Even to them you have poured out a drink offering,You have made a grain offering.Shall I relent concerning these things?