The difference between Blacken and Defame

When used as verbs, blacken means to cause to be or become black, whereas defame means to disgrace.

Defame is also noun with the meaning: disgrace, dishonour.

check bellow for the other definitions of Blacken and Defame

Blacken as a verb (transitive):

To cause to be or become black.
Blacken as a verb (intransitive):

To become black.

Examples:

"The sky blackened as the storm clouds rolled in."
Blacken as a verb:

To make dirty.
Blacken as a verb:

To defame or sully.

Examples:

"Malice delights to blacken the characters of prominent men.'' — Napoleon Bonaparte"
Blacken as a verb:

To cook (meat or fish) by coating with pepper, etc., and quickly searing in a hot pan.

Defame as a verb:

To disgrace; to bring into disrepute.
Defame as a verb (now, chiefly, historical):

To charge; to accuse (someone) of an offence.
Defame as a verb:

To harm or diminish the reputation of; to disparage.

Examples:

"to defame somebody"

Defame as a noun (now, rare, archaic):

Disgrace, dishonour.
Defame as a noun (now, rare, or, nonstandard):

Defamation; slander, libel.