いかん

Usually written in kana. Kanji spelling 行かん

not going (well); not proceeding (as one wishes); bad; not good

Meanings

Expression
not going (well); not proceeding (as one wishes)
bad; not good
hopeless; beyond hope
must not (do, be); should not; ought not to

Example sentences

それはいかんわい！

That won't work!
数検すうけん行いかんかった。別べつにまったく忙いそがしくないが。

I didn't go to the Mathematics Proficiency Test, even though I wasn't particularly busy.