Correct spelling, explanation: adjective different is created by suffixing the verb differ with a suffix -ent, which is used to create adjectives from verbs. It can be also considered a direct borrowing from French différent. Either way, different does not have an alternative correct form.

Definition of different:
Adjective
1. Dissimilar, not similar; not the same.
This dress is based on the same design but in a different color.

Idioms with different:
1. to march to a different drum – to do things not accordingly to previously set standards or conventions
Mark is considered to be weird, but I think he just marches to a different drum and that’s okay.
2. different strokes for different folks – there is no one correct way to please all people; every person needs and likes something else
He’s a really good manager because he knows how to talk to people of all kinds – if different strokes for different folks were a person, that would be him.

Incorrect spelling, explanation: the form differant is not correct because the word is created by means of adding the -ent suffix which means to cause an action. The suffix -ant has a different meaning and is used in a different contexts, usually as a person who performs the verb it’s added to. By that logic, differant would mean a person who differs, which is not correct.

Incorrect spelling

Incorrect spelling

Incorrect spelling

Incorrect spelling