act one's age, not one's shoe size
idiomSynonym of act one's age (“to behave in a mature manner; to avoid being childish”).
- 01
abound in one's own sense
To follow one’s own inclinations and opinions.
- 02
ace up one's sleeve
A surprise advantage of which others are not aware.
- 03
act of Congress
An authorization that is extremely difficult to obtain, especially in a timely fashion.
- 04
act one's age
To behave in a manner appropriate to one's age.
- 05
act out
To perform something specific.
- 06
act the hypocrite
To behave deceitfully or hypocritically; to dissemble.
- 07
act up
To misbehave; to cause trouble.
- 08
afraid of one's own shadow
Exceptionally timid.