simping
mocking
the one-line answer
Excessively pursuing or fawning over someone who does not reciprocate.
Simping is the active form of simp behavior. You are currently doing too much for someone who is not giving anything back. Sending gifts, defending them online, hyping them up when they ignore you. Simping for someone.
mainstream
Your coworker might use this word.
01 / in the wild
hear it move.
roast
bro is simping in her comments and she has no idea who he is.
He is leaving excessive compliments for someone who is not interested.