RichThesaurus
couldn't-care-less
vs
lackadaisical
couldn't-care-less
lackadaisical
adj
Showing no interest, vigor, determination, or enthusiasm.
Lazy; slothful; indolent.
How often have the words
couldn't-care-less
and
lackadaisical
occurred in a corpus of books?
(source:
Google Ngram Viewer
)