There will always be people who take things you say or do the wrong way. That just comes with the territory. If you want to be good at your tech job, you won't

There will always be people who take things you say or do the wrong way. That just comes with the territory. If you want to be good at your tech job, you won't be able to avoid working with other people in some form, so you might as well make the best of it. Your best move is to play the game with both hands above the table, not to avoid playing the game at all. Here's a suggestion for what to say: "Sounds like there's some sort of misunderstanding. I'm not interested in you as anything more than a coworker. We're on the same team and I need to know how to work with you. If you don't want coffee how about we just chat sometime in a meeting room?" If they're still being weird about it, then it's probably worth discussing with your manager because that other person is probably generally difficult to work with. Also to cover your own ass from the specter of future sexual harassment issues if that's what you're worried about. If you're just worried about the other person making it weird... I don't mean to dismiss the concern, but there are plenty of weird people out there, and it's unimportant in the grand scheme of things.