self-centered
Self-centered (adjective) means Concerned mainly with your own interests, needs and feelings, and giving little thought to other people's. Example: “He is too self-centered to notice that his sister is struggling.”
How to use self-centered
Learner’s notesIn plain EnglishOnly really thinking about yourself.
Neutral in form but plainly critical in effect; not a word to use to someone's face lightly.
Keep the hyphen. Self centered without it looks like an error in edited writing.
Fill the gap
Can you complete this real example?
He is too _____ to notice that his sister is struggling.