Can I take my former spouse to court for underreporting of alimony income?

You sure can! That is so illegal! And I am against alimony/maintainance! Each spouse held themselves together before meeting. Tough titty that she doesn't make a living for herself! Stupid woman! You shouldn't have to pay a cent! Probably now you can cut your losses because I doubt you will have to give her much if at all when the IRS finds out! The onl people from that realtionship you owe a dime to are any children that came from that union!