Synonyms of the word

treacherous

• adj. Exhibiting treachery.
• adj. Deceitful; inclined to betray.
• adj. Unreliable; dangerous.

dangerous

• adj. Full of danger.
• adj. Causing danger; ready to do harm or injury.
• adj. (colloquial, dated) In a condition of danger, as from illness; threatened with death.
• adj. (obsolete) Hard to suit; difficult to please.
• adj. (obsolete) Reserved; not affable.

perfidious

• adj. Of, pertaining to, or representing perfidy; disloyal to what should command one's fidelity or allegiance.

unfaithful

• adj. Not having religious faith.
• adj. Not keeping good faith; disloyal; not faithful.
• adj. Not honest or upright.
• adj. (translation studies) which doesn't faithfully render the meaning of the source language; incorrect.
• adj. Adulterous.

unreliable

• adj. Not reliable.

unsafe

• adj. Not safe; dangerous.