To be lazy or idle; to slack off (intransitive) — to neglect to work or make an effort.
彼は休日に怠けるのが好きだ。
He likes to be lazy on his days off.
試験前に怠けると後で後悔するよ。
If you slack off before the exam, you'll regret it later.
怠けてばかりいると評価が下がる。
If you keep being idle, your evaluation will suffer.
To neglect or be neglectful of something (transitive usage) — to fail to do one's duties or skip obligations (e.g., neglect work or school).
彼は仕事を怠けてばかりで、上司に注意された。
He kept neglecting his work and was warned by his boss.
親が子どもの勉強を怠けると将来に影響する。
If parents neglect their children's studies, it will affect their future.