Differences in "is not" words...

[JadeFantasy]

What is the differences between 아닙니다 and 않습니다? I was learning some sentences and this came up and confused me. How do you know when to use either or?
The sentences they were in were: 나는 납자가 아닙니다. And 나는 날씬하지 않습니다. Thanks for your help!

[holdfast]

your first sentence comes from the verb 아니다 and your second sentence comes from the negative verb structure ~지 않다.

아니다 is the negative copula - the opposite of 이다 - it simply means "is not"
저는 남자 아니에요
이것은 내 것 아니에요

~지 않다 can be added to any verb/adjective to make it negative.
이해 하지 않아요
가지 않아요

does that help? ^^

[manyakumi]

Let me make it clearer.

1. Negation of "to be"
noun + 이/가 아니다
나는(subject) 남자(noun)가 아닙니다.
(opp. 나는 남자입니다.)

2. Negation for verbs and adjectives
verb/adjective + 지 않다
나는(subject) 날씬하(adjective stem)지 않습니다.
(opp. 나는 날씬합니다.)

[Chris1]

It also might be interesting to note that 않다 is a contraction of 아니하다.

[JadeFantasy]

Thanks so much! That helped alot! 고맙습니다!