Meaning of CLUTTER in English
■ verb cover or fill with an untidy collection of things: the lounge was ~ed with books and newspapers.
■ noun things lying about untidily.
↘an untidy state.
ME: var. of dialect clotter 'to clot', influenced by cluster and clatter .
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004