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