|So, you sense that your associate's penchant toward garnish pedantry has engendered more than a modicum of vexation. In other words, his tendency to show off his vocabulary is really annoying.|
Having a broad vocabulary is definite strength in many ways, as it can help an individual think more precisely, communicate more effectively, and even sense a higher degree of self-confidence. However, simply filling one's head with a batch of impressive words and then spewing them out to impress or intimidate others typically expresses little more than personal insecurity.
You are not going to change your co-worker's personality, but you can still have an impact on his behavior. You and your associates should let him know that you appreciate his vocabulary, but you do not appreciate the public or private vocabulary lessons. Make sure that he understands that you regard this treatment as insulting and degrading.
Perhaps he will get the message and stop playing these word games with you. If he continues, then you and your associates should have a few words with your manager about this invidious situation.