Justin Thomas apologised for using an "inexcusable" homophobic slur during the third round of the Tournament of Champions on Saturday.
Defending champion Thomas' comment was picked up by a television microphone after he missed a five-foot putt for par on the fourth hole.
"It's inexcusable, first off I just apologise. There's just no excuse. I'm an adult, I'm a grown man - there's absolutely no reason for me to say anything like that. It's terrible," the 2017 PGA Championship winner told the Golf Channel.
"I'm extremely embarrassed. It's not the kind of person that I am.
"Unfortunately, I did it, and I have to own up to it and I'm very apologetic. I'm speechless. I found out when I got done with my round. It's bad. There's no other way to put it.
"I need to do better, I need to be better. It's definitely a learning experience. I deeply apologise to anyone and everybody who I offended, and I'll be better because of it."
Thomas finished his round by carding a five-under 68, which saw him slip three places down the leaderboard for a share of fifth alongside Sungjae Im on 17 under for the tournament.
Ryan Palmer and Harris English finished Saturday's action in Hawaii as joint-leaders, the former producing the best round of the day – a nine-under 64.
Palmer and English hold a one-shot lead over Collin Morikawa, with Daniel Berger two further back in fourth.
English could have been the sole leader had Palmer been issued with a penalty for kicking the soil after seeing a chip on the par-five ninth start to roll back from the elevated green.
Players are not allowed to deliberately alter physical conditions while the ball is in motion, but officials determined he was not attempting to improve his lie.
"There was no intention of me trying to abuse the rule. There was no way, because that ball wasn't even going to be close to where I was at," Palmer said.
"[Rules official John Munch] showed me the video and I looked at it and I go, what am I looking at? And it took me watching it twice to understand what he was talking about.
"In disgust, I kicked a divot, but the ball was five feet away from me where it ended up stopping … there was no intention of me trying to help my ball because there was no way my ball was even close to where I was at.
"I was just discussing with James [Edmondson, his caddie] I hit the wrong wedge on the chip shot, in disgust, and then when I got there, I just kind of did the old kick the divot, p***** off motion."