RichThesaurus
lackadaisically
vs
with all one's might (and main)
lackadaisically
adv
In a lackadaisical manner; without enthusiasm or interest; perfunctorily.
with all one's might (and main)
How often have the words
lackadaisically
and
with all one's might (and main)
occurred in a corpus of books?
(source:
Google Ngram Viewer
)