however

However is a conjunctive adverb, and also a sentence adverb, that signals contrast, contradiction, or a shift in argument. It can connect two independent clauses or insert a parenthetical remark, often drawing attention to a change in direction or nuance.

In formal writing, however is typically linked to the preceding clause with a semicolon and followed by a comma: "The plan was sound; however, it proved impractical." When it begins a sentence, it is usually set off by a comma: "However, the plan remains unproven." In mid-sentence use, it can also be set off by commas: "The plan, however, remains unproven." The placement can affect emphasis and flow, and excessive use can disrupt readability.

Originating from how + ever, the word is formed from Old English and Middle English elements and has long carried a sense of contrast. Its development moved from a general sense of manner or degree to a marker of exception or opposite in thought, especially in written discourse.

Usage and nuance: however tends to be more formal and explicit than a simple "but." It signals a deliberate pivot in argument or a qualification of a previous statement. It is common in academic, journalistic, and professional writing, and less typical in casual spoken language, where alternatives like nevertheless or still may be preferred.

Common pitfalls include misplacing punctuation when connecting independent clauses, overusing however in a single piece, or treating it as a simple synonym for but. Style guides often advise using however judiciously to maintain clarity and rhythm, and to ensure its placement clearly reflects the intended shift in idea.