In eat up, use up and clean up, the small word UP often means "completely", or "all the way to the end". Nothing is going upwards at all.
The weird part
Think about the words themselves. When you eat up your dinner, your plate does not rise. When you use up the glue, nothing floats to the ceiling. Where is the "up"?
Compare these two sentences:
I ate my sandwich.
I ate up my sandwich.
Both describe eating, but the second one says more: the sandwich is all gone. The little word UP adds the idea of finishing the job.
What UP is doing
In many phrasal verbs, UP means "completely" or "until nothing is left":
Please eat up, the soup is getting cold.
We've used up all the paper.
Let's clean up before the bell.
Drink up, the bus is leaving.
Dictionaries show the pattern. The first meaning of eat up is "to consume completely", and use up means to use something until it is gone. The same idea is inside Fill Up, which means to make something completely full.
Not every UP means "completely"
Be careful: UP does many jobs in English, and "completely" is only one of them.
- In Look Up it is about finding information.
- In Pick Up it is about lifting or collecting.
- In Give Up it is about stopping.
So when you meet a new phrasal verb with UP, don't assume. Check what it means, and ask yourself whether something is being finished.
⚠️ Common Mistakes
Where does "it" go? In the middle.
❌ Eat up it!
✅ Eat it up!
Is the job done? Use up only when everything is finished.
❌ I ate up one bite of my sandwich.
✅ I ate up my sandwich, and the plate is empty.
Is UP always "completely"? No.
❌ I'm looking up my keys. Have you seen them?
✅ I'm looking for my keys. / I'm looking up the word.
💬 In a Conversation
Dad: Eat up, please.
Mia: I am eating.
Dad: Eat up. All of it.
Mia: So UP means the broccoli too?
🥡 The OddLingo Takeaway
Next time you see UP in a phrasal verb, ask one question: is something being finished?
If yes, UP may just mean "completely". If not, UP is doing a different job, and it's worth looking the verb up.