Status: musings. I wanted to write up a more fleshed-out and rigorous version of this, but realistically wasn't likely to every get around to it, so here's the half-baked version.
Related posts: Firming Up Honesty Around Its Edge-Cases, Deep honesty
What I mean by 'honesty'
There are nuances to this, but I think a good summary is 'Not intentionally communicating false information'.
This is the only one here that I follow near-absolutely and see as an important standard that people can reasonably be expected to follow in most situations. Everything else here I'd see as either supererogatory, or good-on-balance but with serious tradeoffs that one can reasonably choose to sometimes not make, or good in some circumstances but not appropriate in others, or good in moderation but not in excess.
Forthrightness
...or perhaps frankness?
I was originally inspired to write this up due to a conversation in which I wanted to emphasize the distinction between honesty and forthrightness: where honesty is about not giving false information, what I mean by forthrightness is a tendency not to hold back relevant true information.
Being forthright enables people to justly assume that if you haven't spoken out against something you're likely okay with it, that if you haven't expressed an interest in something you're likely not interested in it, and so on.
Personally, I follow a policy of near-absolute honesty, but am not particularly forthright; I think it's good not to hold back relevant true information without a good reason, but good reasons are not all that uncommon.
Circumspection
I'd describe circumspection as the virtue of holding back information when there is a good reason to do so; the counterpart to forthrightness..
Tact
I don't have as confident a concise description of what I think of tact as meaning, but my best attempt would be something like... recognizing that whatever you say isn't just a transfer of information, it's also a speech act, and avoiding speech