Although it is rarely used, the word, meaningly, exists in English and it is an adverb.
The meaning of meaningly is semantically or from a meaningful point of view in a context or conversation.
Semantics is a branch of linguistics which deals with the scientific study of intended meanings in a discourse of conversation.
Therefore, your example could be restated in the following way:
How are these two sentences different from each other from a semantic point of view?