Not too bright though vs Slow

When to use each in English, with meaning, register, and examples.

Not too bright though

Informal Beyond 10,000 (less common)

Slow

Top 1,000 (very common) A1 adjective

Most formal: Slow Most common: Slow

	Not too bright though	Slow
Pronunciation	🇬🇧 //nɒt tuː braɪt ðoʊ// 🇺🇸 //nɑt tu brayt ðoʊ//	🇬🇧 /["/sləʊ/"]/ 🇺🇸 /["/sləʊ/"]/
Meaning	Not very intelligent.	Not fast; takes time to do something.
Example	She tries hard, but she's not too bright though.	The turtle is moving very slow across the road.
Register	Informal	Neutral
How common	Beyond 10,000 (less common)	Top 1,000 (very common)
CEFR level	-	A1
Part of speech		adjective
Collocations	not too bright though, not very bright, kind of dim, not the sharpest, not exactly a genius	be, prove, seem, extremely, fairly, very, at, slow and steady
Antonyms	-	fast, quick, rapid
Common mistakes	Confusing with 'not very smart', which feels more insulting., Using in formal writing, where it would be inappropriate.	Using 'slow' as a verb instead of an adjective., Confusing 'slow' with 'slowly'., Saying 'more slow' instead of 'slower'.
Usage notes	Typically used in casual conversation. It's a playful or mild way to say someone is not smart, suitable among friends but not in formal contexts.	Used to describe speed. Appropriate in both casual and formal contexts, but avoid using it in very technical discussions about speed measurements.

See it in real clips

Not too bright, though.

Not too bright though

Slow down, turbo!

The Wire › S1 E1

I drink slow.

The Lord Of The Rings › The return of the king

No long, slow sleep of death embalmed.

Slow down, turbo!

The Wire › S1 E1

I drink slow.

Slow

Frequently asked questions: Not too bright though vs Slow

What's the difference between Not too bright though and Slow?

Not too bright though: Not very intelligent. Slow: Not fast; takes time to do something.

Which is more formal: Not too bright though and Slow?

Slow is the most formal of these.

Which is more common: Not too bright though and Slow?

Slow is the most common in everyday English.

Can you show an example of each?

Not too bright though: She tries hard, but she's not too bright though. Slow: The turtle is moving very slow across the road.

Can I use Not too bright though and Slow interchangeably?

Not always. Not too bright though and Slow are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.