Can "rightly" be used as an adjective? [closed]

I am writing an essay for school and I would like to hear opinions on the matter.

The context is, "...we can therefore infer that stereotypes are seen by the general consensus in a negative light. The rightly reason for this is because of the...".

In this case I mean something along the lines of "well-grounded".

Thank you very much in advance.

Solution 1:

I see no evidence that rightly is ever used as an adjective, at least when preceded by the. In the Corpus of Contemporary American English (COCA) we find such examples as

the rightly regal and intelligent spirit
the rightly played language games
the rightly guided one
the rightly accused
the rightly hated apartheid regime

Searching google books for "the rightly" produces similar hits. In all cases, rightly modifes an adjective or a participle. When this is combined with the observation that no dictionary lists rightly as an adjective, we can conclude that the usage you suggested does not result in an acceptable English sentence.

Instead, use some alternative such as

the obvious reason for this is…
the clear reason for this is…
the strong reason for this is…
the well-grounded reason for this is…
the well-justified reason for this is…