easily
An unwary observer could easily mistake this constellation for a comet.

cannot
You can't mistake him. He has long red hair.

for
I'm sorry. I mistook you for George.
People often mistake us for sisters.

there is no mistaking sth
There was no mistaking the admiration in his eyes.

big, colossal (esp. AmE), great, huge
It is a great mistake to assume that your children will agree with you.

bad, dreadful, fundamental, ghastly (esp. BrE), grave, horrible (esp. AmE), serious, terrible
costly, expensive
This dress was an expensive mistake.

disastrous, fatal, tragic
embarrassing
elementary, little, simple
All those problems because of one little mistake!

common
genuine, honest
deliberate
past
The company has learned from its past mistakes.

careless, dumb (AmE), foolish, stupid
grammar, grammatical, spelling

make
I'm sorry, I made a mistake.

commit
They all commit similar mistakes.

repeat
learn from
pay for
Ordinary people are paying for the government's mistakes.

discover, realize
Too late, she realized her mistake.

avoid
We can help you avoid costly mistakes.

acknowledge, admit, admit to, recognize
correct, erase, fix (AmE), put right, rectify, undo
regret
forgive
point out
The teacher kindly pointed out the mistake.

eliminate
It isn't possible to eliminate all mistakes.

happen, occur
Mistakes are bound to happen sometimes.

by mistake
I picked up the wrong bag by mistake.

mistake about
I made a mistake about her.

all a mistake
I kept telling myself that it was all a terrible mistake.

an easy mistake to make
Don't worry about it—it's an easy mistake to make!

make the mistake of doing sth
A lot of people make the mistake of thinking that getting results is all that matters.

make the same mistake
Don't make the same mistake as I did.