The following can be grounds for opposition:

• proprietary rights
• breach of copyright
• the mark is functional
• the mark is descriptive
• likelihood of confusion
• the mark is not distinctive
• the mark is misleading, deceptive or disparaging
• rights in a personal name
• the mark is against public policy or principles of morality
• the mark is generic
• registration of the mark would injure the opposing party
• unauthorized use of specially protected emblems or national insignia
• famous or well-known marks