- The project gives signs of too much uncertainty.
- The project gives too much uncertainty.
If I am trying to use sense 5c of this dictionary, would one of the sentences above be wrong? Is signs of needed?
Sentence #1 is grammatically correct (though awkward) by your definition 5c, and sentence #2 is incorrect.
Definition 5c is a situation where "to give" means "to show (something)." "Uncertainty" here is an intangible element that cannot be "shown" in itself, but rather must be shown through tangible elements like "signs" of uncertainty. That is why sentence #2 is wrong for definition 5c.
The definition you refer to gives the meaning ‘show’. If that is what you want to say, then the first sentence is what you need. The second, if it were to be used at all, suggests that the project itself, its mere existence, creates uncertainty.
Idiom does not necessarily follow dictionaries. Idiomatic constructions would be:
The last offering is probably closest to the "give" domain of meaning.
And possibly even:
Although to my reading that might be too strained or artificial.