Webster's Revised Unabridged Dictionary · 1913

Disadvantage

Disadvantage (?; 48, 61) , noun

[Compare French désavantage.]

1.
Deprivation of advantage; unfavorable or prejudicial quality, condition, circumstance, or the like; that which hinders success, or causes loss or injury.
I was brought here under the disadvantage of being unknown by sight to any of you. — Burke
Abandoned by their great patron, the faction henceforward acted at disadvantage. — Palfrey
2.
Loss; detriment; hindrance; prejudice to interest, fame, credit, profit, or other good.
They would throw a construction on his conduct, to his disadvantage before the public. — Bancroft

Disadvantage , transitive verb

[Compare French désavantager.]

To injure the interest of; to be detrimental to.