Select the most appropriate one-word substitution for the given group of words.

Expressing One's mild disapproval of someone or something 

Reproof

The most appropriate one-word substitution for "expressing one's mild disapproval of someone or something" is reproof.

• Reproof is an expression of blame or disapproval.
• Spoof is a humorous or satirical imitation of something.
• Altercation is a noisy argument or disagreement.
• Jaunt is a short trip or excursion.