Correct spelling, explanation: too big is an idiomatic expression used to indicate excess or something being larger than necessary or desired. It is used when you want to say that something is more than what it should be. On the other hand, to big does not have any specific meaning in English. Too is an adverb, and it is used before an adjective (such as big) to modify or intensify its meaning. In this case, too big means excessively big or larger than needed. Correct grammar requires the use of too before big to convey this meaning accurately.

Definition of too big:
phrase, excessively large
The shirt is too big for me; I need a smaller size.
The suitcase was too big to fit in the overhead compartment on the plane.

Collocations with too big:
Some most commonly used collocations include:
1. Too big to handle: refers to a situation or task that is too difficult or complex to manage or deal with effectively.
The project became too big to handle on my own, so I had to ask for help from my team.
2. Too big to fail: used to describe a company or organization that is considered so large and significant that its failure would have severe consequences for the economy or society.
The government bailed out the banks because they believed they were too big to fail.
3. Too big for one’s shoes: describes someone who is overly confident or arrogant, thinking they are more capable or important than they actually are.
Ever since he got promoted, he’s been acting too big for his shoes, thinking he knows everything.
4. Too big for its britches: similar to the previous collocation, this phrase refers to something or someone acting as if they are more important or capable than they truly are.
The startup company’s arrogance made them seem too big for their britches, and they eventually faced financial difficulties.

Incorrect spelling, explanation: to big is not a grammatically correct phrase and doesn’t have any specific meaning in English. The word to is a preposition or part of an infinitive verb, and it is not used in this context to modify the adjective big. The correct form is always too big when you want to convey the idea of something being excessively large or more than what is needed. Too is the adverbial form. Adverbs can modify adjectives, which is why it is correct to use them before the adjective big.