The Urban Dictionary defines whateverism as 'an unyielding attempt to convert simple moral truths into limitless shades of grey'.
He’s a whateverist, a little too idealist
Who keeps on saying in every way... Whatever
A whateverist, a funny indifferent
Who says rightly or wrongly... Whatever
The translation of Serge Gainsbourg's l'aquoiboniste is more or less adequate, I think. Jane Birkin's brand new version is Track 6 on the Spotify stream of the new album.
At the moment I find the song particularly pertinent.