Sorry for the poor title.
Is there a name/category of words with the property that using "not" before them does not give a standard negation in a way similar to the given examples?
The two examples, which will help me make this question clear, are "recommended" and "supposed."
In both of these cases, "not recommended" seems to mean "recommended to not," while "not supposed" seems to mean "supposed to not."
"He did not jump across the pond."
What did he do? Well, whatever he did, it did not involve jumping across the pond.
"My professor did not recommend that I take both classes at once." This reads (to me) as though the professor gave positive advice against taking both classes. If "not recommended" meant a simple lack of recommendation, then this sentence would apply if I didn't speak to my professor, or if we simply had lunch together without discussing my classes.
If I say "we are not supposed to wear button up shirts to work", it reads as though it is against policy to wear button up shirts ("supposed to not") while if "not supposed" simply meant a lack of supposition, then this statement would be true as long as other types of shirts are allowed.
Are there other examples of this? Am I being clear?