How do I make XTerm not use bold?

If you set the same font for bold and normal font it might work.

I set the fixed font for both like:

xterm*font: fixed
xterm*boldFont: fixed

If you then do xrdb -load and start a new term it was back to not being bold :)

Setting allowBoldFonts property works for me

Add the following line in your ~/.Xresources

XTerm*allowBoldFonts: false

X resources aren't reloaded until you reload the X windowing system, and they aren't polled unless you restart the executable which is doing it. Try running

xrdb ~/.Xresources

in your current session. Then start another xterm. The next time you start X (relogin or reboot) the resources should be read automatically.

Another thing to try is to use a wildcard to make sure that it is picking up the resource correctly. Use

XTerm*boldMode: false 

instead.

Yet another thing to check is that you are actually running xterm when you run a terminal process. If not, you will need to change the fonts with a different resource.