lie behind (something)

to explain or be the reason for something.

I wonder what lay behind his decision to quit school.

• whet someone's appetite
• which way the wind is blowing
• while away
• while away something
• while back is turned
• while someone's back is turned
• While the cat's away .
• While the cat's away the mice will play.
• while the going is good
• whip into shape
• whipping boy
• whip-round
• whip someone into shape
• whip something into shape
• whip up
• whip up something
• whistle-blower
• whistle-stop tour
• whistling in the dark
• white-bread
• white-collar
• white elephant
• white knight
• white lie
• whiter than white