Opposing:
* Versus: (used in formal contexts, especially when referring to a competition or conflict)
* Contrary to: (emphasizing opposition to a statement or belief)
* In opposition to: (formal, similar to "against")
* Opposed to: (expresses a personal dislike or disapproval)
Preventing:
* Precluding: (making something impossible)
* Obstructing: (blocking or hindering something)
* Impeding: (delaying or hindering progress)
Protecting from:
* Shielding: (acting as a barrier to protect something)
* Defending: (taking action to protect something from harm)
* Safeguarding: (preserving something from harm or loss)
Other:
* Adverse to: (unfavorable or harmful)
* Hostile to: (showing strong dislike or opposition)
* Contrary: (opposite or different)
It's important to consider the specific context of your sentence and choose the synonym that best conveys the intended meaning.