admonish, dissuade
諫 centers on using words to correct someone's course: admonishing or dissuading them from a wrong path.
諫 combines 言 (words) with 柬, which likely contributes the sound and the idea of selecting or separating, suggesting using words to separate someone from a wrong course.
Words (言) that select or separate (柬) someone from a bad path: 諫 means to admonish or dissuade.
For カン, imagine a can of admonishing words: you open the can and out come words that dissuade you. Can -> カン.
admonition; remonstrance; expostulation
remonstrance; remonstration; admonition; protest; reproof; expostulation; advice; counsel
personal admonition; remonstration
dissuasion
committing suicide (to remonstrate or dissuade one's lord); preparing to die in an effort to dissuade one's lord
retainer who dares to dissuade his lord
indirect remonstrance; exhortation by insinuation