1. not relating to or involving diplomacy or diplomatic relations
2. lacking tact or skill in dealing with people; blunt or insensitive in manner

Examples

• The meeting was conducted through nondiplomatic channels.
• His nondiplomatic approach to the negotiation offended several participants.
• She gave a nondiplomatic response that hurt his feelings.
• The company’s nondiplomatic handling of the crisis damaged their reputation.
• Trade discussions continued through nondiplomatic contacts.
• His nondiplomatic manner made him unsuitable for customer service.
• The ambassador’s nondiplomatic comments caused an international incident.