If "treacherous" refers to being dangerous and unreliable:
* Safe
* Reliable
* Trustworthy
* Secure
* Stable
If "treacherous" refers to being deceitful and untrustworthy:
* Honest
* Loyal
* Faithful
* Trustworthy
* Sincere
If "treacherous" refers to being difficult and dangerous to navigate:
* Easy
* Safe
* Accessible
* Clear
* Smooth
Examples:
* The opposite of a treacherous path is a safe and easy one.
* The opposite of a treacherous friend is a loyal and trustworthy one.
* The opposite of a treacherous storm is a calm and peaceful one.
Therefore, the most accurate opposite of "treacherous" depends on the specific context and the intended meaning.