What is meant by the term "formal" in this question? In American English, the word reason is both a noun (the cause or basis of something) and a verb (to think in a logical manner). Neither of them has any special sense of formality, if that's what is being asked.
Formal is not a compound word.
The formal word for sister is "sibling."
No, formal is an adjective, the adverb is formally.
The formal word for grandmother in Portuguese is "avó."
what is another word for promise? A vow or an oath
Informal? semi-formal
Formal is an adjective.
Another word for a formal speech is an oration or a discourse.
A formal disapproval is a reprimand.
yes
"Occur" would work, however, happen is appropriate in most situations.
The word used to introduce a formal debate proposition is "resolved."