Here are some synonyms:
* Indifferent
* Careless
* Lazy
* Unmotivated
* Half-hearted
* Lethargic
Here are some examples of how to use "lackadaisical" in a sentence:
* "The students were lackadaisical about their homework, turning in sloppy work."
* "The team's lackadaisical performance led to their loss."
* "Her lackadaisical attitude towards her job made her colleagues frustrated."
Essentially, it describes someone who is not putting in effort or care, showing a general lack of energy and interest.