false to one's obligations or allegiances; not loyal; faithless; treacherous.
Origin
1470-80; < Middle Frenchdesloial,Old Frenchdesleal, equivalent to des-dis-1 + lealloyal
Related forms
disloyalist, noun
disloyally, adverb
Synonyms
unfaithful, perfidious, traitorous, treasonable.
Examples from the web for disloyal
Even good publicity could make a banker uppity, disloyal and limelight-seeking.
How many fall into the disloyal categories is not known.
These figures are viewed as disloyal to the cause of conservatism.
No one who participates in this conversation should be branded as disloyal or a traitor.
He has purged the military of the disloyal officers who betrayed him.
Many viewed his action as disloyal and opportunistic.
Renee was fired for her disloyal behavior and her poor judgment.
We can't have these disloyal people running around and giving comfort to the enemy.
British Dictionary definitions for disloyal
disloyal
/dɪsˈlɔɪəl/
adjective
1.
not loyal or faithful; deserting one's allegiance or duty
Derived Forms
disloyally, adverb
Word Origin and History for disloyal
adj.
early 15c. (implied in disloyally), from Old French desloial, desleal (Modern French déloyal) "treacherous, false, deceitful," from des- (see dis-) + loial (see loyal).