The best replacement for underflow is overflow.

The best alternatives to underflow are rated as following:
★★★★★  overflow

Your alternative for underflow is not listed? Suggest!

No companions for underflow have been suggested so far.
You have in mind a companion for underflow and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of underflow in all years. Click on graph for more.