act on

In addition to the idioms beginning with act

• act of faith
• act of God
• act on
• act one’s age
• act out
• act up
• act upon

also see:

• catch in the act
• clean up (one’s act)
• do a disappearing act
• get in the act
• get one’s act together
• hard (tough) act to follow
• high-wire act
• in the act of
• put on an act