看不起 + 某物品 (something)
表示 觉得这个物品没有价值，不值得拥有。
Indicates that you think that thing is worthless or not worth having
看不起 + 某人 (someone)
表示 觉得这个人某方面能力或某方面不好，带贬义。
Indicates that you think this person is, in some respect, bad. Pejorative term.
看不上 + 某人 (someone)
觉得这个人不适合。 比如团队需要人，选择男女朋友时。
You think this person is unsuitable. For instance, when a team is selecting new members, or when one chooses a boy or girl friend.
