I just found out that the company head/HR who is going to be interviewing me is a former research colleague's father, and he most likely knows that I know his daughter since I have my research experience on my resume.
I decided to save myself the awkwardness and withdraw my application. I don't want to outright lie (i.e. saying that I have been hired with another company) but I also don't want to sound rude by not giving any reasons. How can I explain withdrawing my application?
Just ghosting is probably not the best option, but you can withdraw by saying something that doesn't really say anything. Contact them and say (or write) something like:
After further research, I don't think this job is the right one for me at this time. Therefore, I would like to withdraw my application, so that you don't spend an interview slot on me. Thank you for your time and consideration, and I wish you the best in your employee search.
That does give them the option to not waste their time by being ready to interview you and you not showing up, allows them to get someone else qualified to interview. You are being considerate, and that will look better if you run across any of the potential interviewers in the future.
