indefeasible
adjective
in·de·fea·si·ble ˌin-di-ˈfē-zə-bəl 
: not capable of being annulled or voided or undone
an indefeasible right
indefeasibility
ˌin-di-ˌfē-zə-ˈbi-lə-tē
noun indefeasibly
ˌin-di-ˈfē-zə-blē
adverb 
Did you know?
We acquired "indefeasible" in the mid-16th century by combining the English prefix in- ("not") with "defeasible," a word borrowed a century earlier from Anglo-French. "Defeasible" itself can be traced to an Old French verb meaning "to undo" or "to destroy." It's no surprise, then, that something indefeasible is essentially "un-undoable" or "indestructible." Another member of this family of words is feasible, meaning "capable of being done or carried out." Ultimately, all three - "indefeasible," "defeasible," and "feasible" - can be traced back to the Latin verb facere, meaning "to do."
Word History
First Known Use
1548, in the meaning defined above
Legal Definition
indefeasible
adjective
in·de·fea·si·ble ˌin-di-ˈfē-zə-bəl
: not capable of being annulled or voided
an indefeasible right
indefeasible
adjective
as in indestructible
Synonyms & Similar Words
Relevance
- indestructible
- indefectible
- permanent
- indissoluble
- eternal
- deathless
- imperishable
- immortal
- indelible
- everlasting
- unending
- undying
- enduring
- perpetual
- endless
- inexpungible
- persistent
- lasting
- durable
- timeless
- stubborn
- ceaseless
- abiding
- unfailing
- steadfast
- unfaltering
- continuous
- standing
- uninterrupted
- dateless
- unceasing
- unbroken
- long-lived
- unremitting
- stable
- incessant
- continual
- continuing
- steady
Antonyms & Near Antonyms
- evanescent
- transitory
- ephemeral
- momentary
- fleeting
- provisional
- fugitive
- passing
- fugacious
- temporary
- mortal
- transient
- interim
- short-lived
- impermanent
- short-term