The adjective sluggish means a thing that moves, reacts and operates very slowly, other than what is expected or what is normal.

Synonyms are heavy, inactive, slack, or apathetic.

The word origins from Middle English (mid-15th century) slugge meaning “lazy person” plus –ish. In the early 13th century, its earlier adjective was sluggi.

I hate a sluggish person the most.

Her sluggish walk annoyed her friends.

The finance department is too sluggish to process the documents.