IPA: /ʌnˈklʌtəd/
KK: /ʌnˈklʌtərd/
Not messy or filled with too many things; organized and tidy.
The office was bright and uncluttered, making it easy to focus on work.
Uncluttered → It is formed from "un-" (meaning not) and "clutter" (from Middle English *cluttre*, meaning to make a mess or to confuse). The word "uncluttered" means not having a mess or being free from confusion.
Think of 'not' ('un-') having a 'mess' ('clutter') — that's why uncluttered means free from mess.