I think an acceptable alternative to the name "wife beater" undershirt is the "tank" undershirt, sometimes known as a "workout" shirt. Any of these names is likely to raise questions as none seem to be universally used.
example
http://www.bestforminc.com/tank-top.cfm
It certainly would be nice to have universal definitions on all clothes types, but that seems as elusive as a nationwide concealed carry right. Can you imagine if drivers licenses were equally "patchwork"?
Good luck.
Lost Sheep.