The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
Self-Proclaimed Liar or it might simply be a Lampshade Hanging of how duplicitous the character is.
Can be part of the characterization of a Lovable Traitor - they're not loyal, but it's in a way where, say, they'll tell you they're being bribed and give you a chance to make a better offer.
This is also the corollary to Beware the Honest Ones- you know this person is going to do whatever benefits them, and therefore can trust them to do that.
@rasterax THATS IT THATS THE ONE
Stand up against pinkwashing, don't fall for propoganda
You know when a character has no scruples about being dishonest, sleazy, hypocritical, etc etc etc, to the point where they will come right out and say it. Like they might not necessarily be a terrible person, they just know they're not morally upstanding.
I have two specific examples I can think of. In Succession when Kendall asks Stewy if he can have his support in a board vote and Stewy goes "I can promise you I'm ethically, morally, financially behind whoever wins". Stewy's notorious for this, there's also another line where he simply goes "I'm kind of a selfish person, so."
The other example I can think of is the bit in The Newsreader where Gerry complains about a series of terrible joke recommendations his CEO gives him for his comedy show. When Helen says "but you ignored him, right?", Gerry says "oh no I said them, but I have no integrity, you stick to your guns."
The important thing is that these characters admit to their insincerity or selfishness or whatever, and furthermore, don't have shame or a desire to improve. Is this a thing, or am I going insane.