Correct spelling, explanation: the phrase a bit consists of two words: a – an indefinite article and bit – a noun that means a small piece, amount, or degree of something. This phrase is commonly used in English to indicate a small quantity or a slight degree of something. Abit is not a valid word in standard English. Some people mistakenly write a bit as one word, but this is incorrect.

Definition of a bit:
Phrase, a small amount of anything; also, a short period of time
Can you turn the music down a bit?
He was a bit late to the meeting.

Collocations with a bit:
Some of the most commonly used collocations include:
1. A bit of a surprise: something unexpected but not shocking.
It was a bit of a surprise to see him at the party.
2. A bit of a shock: something slightly shocking, but not extreme.
The sudden price increase was a bit of a shock to everyone.
3. A bit of a challenge: something that is somewhat difficult but not impossible.
Learning a new language can be a bit of a challenge at first.
4. A bit of a disaster: a situation that went somewhat wrong, often humorously.
My attempt at baking a cake was a bit of a disaster!

Incorrect spelling, explanation: abit is a mistake because a bit is a two-word phrase, not a single word. A is an article (just like in a car, a dog, etc.), and bit is a noun that means a small amount or a small piece of something. Since these are two separate words with distinct meanings, they must remain separate in writing. There is no such word as abit in English dictionaries. If you write abit instead of a bit, it will be considered a typo or an incorrect spelling.

Incorrect spelling