What does "I can't agree with you more" mean?

Solution 1:

"I cannot agree with you more." means that I agree with you to a complete extent, making it impossible for me to agree with you to a greater extent.

"I cannot agree with you any more." means that I can no longer agree with you. I agreed with you before, but that has come to an end.

"Anymore" is a somewhat controversial word which is equivalent to "any more", but does not substitute for "any more" in all uses: you would never write "I don't need anymore supplies".

See for instance: http://alt-usage-english.org/anymore.html

Solution 2:

Sentences 1 are 2 similar, but they are different from sentence 3:

"I can't agree with you more"

To say that "I can't agree with you more" means you fully and absolutely agree with someone. You can't possibly agree with them more than you already are with this person. 100% agreement with everything said person is saying.

"I can't agree with you any more"

This sentence is kind of the same as the last one. You aren't able to agree with someone at any higher degree than you are now.

"I can't agree with you anymore"

The words "anymore" and "any more" are very different, please be careful!

To say "I can't agree with you anymore" means you can no longer agree with someone. That's how the word "anymore" is different than the words "any + more." You are no longer able to agree with that person. Here are some examples of using the word "anymore" vs "any + more":

1. • "I can't row this boat any more" : You cannot row the boat more than you are at the present moment
   • "I can't row this boat anymore": You are no longer capable of rowing the boat
2. • "I can't push this box any more": You cannot push the box with more effort than you are pushing it at the present moment
   • "I can't push this box anymore": You are no longer capable of pushing the box

Hope this helps!