Auto-antonyms are two words that are pronounced and spelled the same way, but have opposite meanings. For example, weather can mean to erode, or to endure. You can trim a tree by cutting away branches, or by adding decorations.
Auto-antonyms are also a kind of homonym (two words spelled and sounding the same with difference meanings). Homonyms don’t cause too many problems for cataloguers, since they’re spelled the same way. Homophones, however, can be another matter: these words have the same pronunciation, but different meanings and sometimes different spellings. This can lead to typographical slipups like mixing up creak and creek, or carat, caret, and carrot.
Antonymn* is a high probability typo on the Ballard List, occurring 28 times in OhioLINK.