According to
 

What's the opposite of according to?

Context is needed, but some of these might do:

in disagreement with
inconsistent with
incompatible with

I'm not sure there is a true direct opposite. Rusty's choices are the same I would say, but they are not really "opposites" to the phrase itself. Can you provide some context for us?

You can say: not according to (me).

This term is often used when you disagree with someone.

What's the opposite of segun.

En desacuerdo con el titular

in disagreement with
at variance with
at odds with

opposed to

How about "contrary to"?

What about disagreeing with?

I prefer Marmoset's contrary to. This works most of the the time. Some of the other choices (like my not according to) don't always work in all circumstances. Others sound awkward.

:)

It came to me suddenly while washing the dishes.