Lazy Person
noun
A lazy someone is a lazy person.
怠け者 describes someone who habitually avoids effort. Note that when written in katakana as ナマケモノ, it usually refers to the animal. Because, well… Sloths move slowly and look kinda lazy, you know?
The readings for this word are both kun'yomi readings. You've learned both of these readings by now so you should be able to read this on your own.
彼は会社で一番の怠け者だが、一番成績を上げている。
He’s the laziest person at the company, but he also gets the best results.