1. a person who teaches or instructs; a teacher or instructor
Usage: formal or literary; often implies someone who is pedantic or overly concerned with instruction
2. a person who is didactic; someone who is inclined to teach or moralize in a tedious or overbearing manner
Usage: often pejorative

Examples

• The professor was more of a didact than an inspiring mentor.
• She approached every conversation like a didact, always eager to correct others.
• Ancient Greek didacts developed early methods of systematic instruction.
• He had the manner of a didact, lecturing rather than conversing.
• The didact's rigid teaching style left little room for student creativity.
• Some view him as a helpful didact; others find him insufferably pedantic.