What are the definitions of “act up”?
Learn how to use these expressions through these examples
- 1Behave badly or strangely.
My computer's ACTING UP; I think I might have a virus.
What’s the most common meaning of the phrasal verb “act up”?
The most common meaning of the phrasal verb act up is to behave badly or strangely. It can be used to describe people, animals, or even objects, such as machines or devices, that are not functioning properly or behaving as expected.
What are the different verb forms of “act up”?
| Root Verb | act up |
| Third Person Singular Present | acts up |
| Present Participle | acting up |
| Simple Past | acted up |
| Past Participle | acted up |
Example
My computer is acting up; I think I might have a virus.
Example
Her car acts up whenever it's cold outside.
Example
The printer is acting up again, so we can't print the documents.
Example
His knee acted up during the game, so he had to stop playing.
Example
The children had acted up all day, making it difficult for the teacher to teach.
What kind of phrasal verb is “act up”?
Notes from a Native English Speaker
What is a transitive and intransitive verb? - A transitive verb always has an object after it. (Example: Sam bought a car.) - An intransitive verb never has an object.(Example: She laughed loudly.)
Intransitive verb
“act up” is an intransitive phrasal verb because it doesn't require an object to complete its meaning. It forms a complete sentence without an object.
Example
The dog acted up when it saw the mail carrier.
Example
My phone acted up and wouldn't let me make any calls.
Notes from a Native English Speaker
What is a separable and inseparable phrasal verb? - A “separable phrasal verb” can be separated with an object between the verb and particle. - An “inseparable phrasal verb” cannot be separated by an object.
Inseparable
“act up” is an inseparable phrasal verb. This means that you can’t place an object between the verb and the particle, otherwise, it changes the meaning of the phrasal verb.
Example
The dog acted up when it saw the mail carrier.
Example
My phone acted up and wouldn't let me make any calls.
What are common phrases and expressions that include the phrasal verb “act up”?
Good things to know
Does “act up” have an informal or formal tone?
Act up is generally considered informal and is more commonly used in everyday conversations. In more formal settings, alternative phrases such as 'malfunction,' 'misbehave,' or 'behave inappropriately' may be more appropriate.
