Not trustworthy, in any sense: as, an untrustworthy servant; an untrustworthy boat.

adjective. Not deserving of trust; unreliable.

adjective. not worthy of trust or belief

"Rejoined the wolf, I have no faith in thy word, for sages have said, ‘Whoso practiseth trust in the place of hate, erreth;’ and, ‘Whoso trusteth in the untrustworthy is a dupe; he who re-trieth him who hath been tried shall reap repentance and his days shall go waste; and he who cannot distinguish between case and case, giving each its due, and assigneth all the weight to one side, his luck shall be little and his miseries shall be many.’"

accurate  faithful  reliable  sincere  true  

dishonest  unreliable  

devious  fly-by-night  shady  shifty  slippery  

trustworthy  

amoral  deprave  dishonest  fallacious  fickle  

dangerous  desultory  doubtful  dubious  fly-by-night