machiavellian
When you wait a little before replying so you don't look like you're begging for attention.
He saw the message at 9 p. m. and didn't reply until 10:30 p. m.
She got the text at 8 a. m. but waited until 11 a. m. to reply.
He saw the message, then went to play video games for an hour before replying.