object lesson vs word of advice

object lesson and word of advice both are nouns.

Word	Noun	Adjective	Verb	Adverb
object lesson	Yes	No	No	No
word of advice	Yes	No	No	No

As nouns, word of advice is a hypernym of object lesson; that is, word of advice is a word with a broader meaning than object lesson:

object lesson: punishment intended as a warning to others
word of advice: cautionary advice about something imminent (especially imminent danger or other unpleasantness)

Other hypernyms of object lesson include admonition, monition, warning.

object lesson (noun)	word of advice (noun)
punishment intended as a warning to others	cautionary advice about something imminent (especially imminent danger or other unpleasantness)