in motion.

He started to run, but a rifle shot caught him on the wing.

Usage notes: based on the literal meaning of on the wing - flying: The sight of so many enormous birds on the wing filled me with awe.

• in the eyes of someone
• in the eyes of the law
• in the face of
• in the face of something
• in the family way
• in the fast lane
• in the final analysis
• in the first place
• in the flesh
• in the fullness of time
• in the grand scheme of things
• in the great scheme of things
• in the grip of
• in the grip of something
• in the groove
• in the hands of
• in the hands of someone
• in the heat of
• in the heat of something
• in the heat of the moment
• in the hole
• in the hot seat
• in the house
• in the interim
• in their infinite wisdom