Unsightly means unpleasant or unattractive to look at. When something is unsightly, it's the opposite of beautiful or pleasing: it makes you want to look away rather than admire it.

An unsightly pile of trash on a sidewalk ruins the appearance of an otherwise clean street. An unsightly stain on your shirt might make you rush to change before school photos. Weeds growing wild in a garden can create an unsightly tangle that blocks the view of the flowers.

The word usually describes things that could or should look better. A scar might be unsightly, but it's still part of someone's story. An old building with peeling paint and broken windows looks unsightly, though it might have been beautiful once. Notice that unsightly focuses on appearance, not function: an unsightly bicycle with chipped paint and rust spots might still ride perfectly well.

People use unsightly when they want to be polite about saying something looks bad. Instead of calling your cousin's new haircut terrible, you might think to yourself that it looks a bit unsightly. The word suggests that something mars or spoils the view, like how a single piece of litter can make a whole park look less inviting.