Business attire for men usually means polished, professional clothing that fits the workplace, with the exact level ranging from business casual to business formal. In the most formal version, it typically includes a suit, dress shirt, tie, leather shoes, and a matching belt.

What men usually wear

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Dress level Typical clothing
Business formal Dark suit, dress shirt, tie, leather dress shoes, matching belt
Business casual Dress shirt or collared shirt, chinos or tailored trousers, loafers or other polished shoes, usually no tie

Simple rule

A safe default for men is: wear something neat, fitted, and conservative enough for the setting. Dark or neutral colors, clean shoes, and minimal accessories are the most common recommendations.

Easy example

For a standard office or interview, a navy or charcoal suit with a white shirt and a simple tie is a classic business-attire outfit. For a more relaxed office, a collared shirt with chinos and loafers is often acceptable.

TL;DR: Men’s business attire is professional, tidy clothing; in formal settings that means a suit and tie, while in business casual settings it usually means a collared shirt, tailored trousers or chinos, and polished shoes.