but

conj. used to introduce a statement that is different from what you just said.

conj. used to introduce a clause that contrasts with or contradicts the preceding statement.

“I wanted to go for a walk, but it started to rain.”

“The initial results of the study were promising, but the research team cautioned that further peer-reviewed trials were necessary before drawing conclusions.”

prep. used to mean 'except' or 'apart from'.

prep. used to indicate an exception to a preceding general statement, often following negative or universal quantifiers like 'no one' or 'everyone'.

“Everyone in the office attended the meeting but the manager.”

“The committee found no alternative but to postpone the project until the necessary funding could be secured through private investment.”

adv. used to mean 'only' or 'just'.

adv. used as a restrictive adverb meaning 'merely' or 'no more than'.

“He is but a child and does not understand the rules yet.”

“The grand cathedral, once a symbol of imperial power, was now but a crumbling ruin reclaimed by the surrounding forest.”

Literary

adv. used at the end of a sentence to mean 'however'.

adv. used as a sentence-final conjunctive adverb to indicate a contrast with a previous statement.

“It was a very expensive car, but.”

“The weather was miserable for the entire trip; we had a great time, but.”

British English · Dialect

n. a reason for not doing something or a doubt.

n. an objection, caveat, or condition, typically used in the plural phrase 'no ifs, ands, or buts'.

“I want you to finish your homework now—no buts.”

“The contract was signed without any 'buts' from the legal department, much to the relief of the negotiating team.”