Ephraim feeds on wind, And chases the east wind. He continually multiplies lies and desolation. They make a covenant with Assyria, And oil is carried into Egypt.
Feedeth on wind ... east wind ..." This is a similar metaphor to the one used earlier  (Hosea 8:7), "Sowing to the wind, reaping the whirlwind." What is clearly meant is the vanity and fruitlessness of Ephraim's self-directed efforts to secure his safety and prosperity while pursuing a rebellious course contrary to the will of God.