I’m looking for advice on what to do about a coworker who has been treating me unprofessionally and is not responding to feedback that the way he communicates is not workplace-appropriate.

This is someone I’ve worked with in the past but not closely. At our last job he had a reputation for being very technically skilled, but arrogant and difficult to work with.

After we both quit our jobs several months ago (for independent reasons), he reached out to me to offer a contract job at a startup he was working with. Eager for work, I accepted.

We’ve been working together for about a month and are running into some communication issues. When I try to engage with him on projects, he often responds in a way that comes across as dismissive or condescending. (Note that we’re peers on the team and expected to be working together.)

For example, we were recently designing a table in a database to store a type of transaction. When I asked for clarification on a detail he said, “have you ever seen a transaction table”? Not only was his response not helpful, but I felt belittled by the question. It’s not uncommon for him to take that kind of tone with me.

I asked him to please treat me with a little more respect in conversation and suggested being a bit gentler when offering feedback. He apologized, but went on to tell me in great detail what my deficiencies are as a colleague. For instance, that I “have a lot to learn about schema design, databases, and working on an engineering team”. He said he’s also frustrated by my inability to articulate my thoughts, and recommended “using the Internet” to educate myself. Coming from someone who has less work experience than I do and is not my superior, I found those statements to be a little out of bounds.

At this point I’ve tried to resolve the issue with him personally and I’m considering taking it to our supervisor. The dilemma is — is it worth potentially burning the bridge and “throwing him under the bus”? I’d prefer not to, especially since he connected me with the company in the first place, but our dynamic is making it hard for me to get my work done.