This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Inexcusable; unpardonable: indefensible behavior.

adj. Invalid; untenable: an indefensible assumption.

adj. Vulnerable to physical attack: indefensible borders.

adj. Not defensible; not capable of being defended; vulnerable.

adj. Incapable of being justified or excused; inexcusable; unpardonable.

adj. Incapable of being explained; untenable; insupportable; invalid.

Not defensible; not capable of being defended, maintained, vindicated, or justified; unjustifiable; untenable

Not defensible; that cannot be defended, maintained, or justified, by either force or speech: as, an indefensible frontier; conduct that is indefensible.

adj. not able to be protected against attack

adj. (of theories etc) incapable of being defended or justified

adj. incapable of being justified or explained

"During a visit to Washington last month, Prime Minister Benjamin Netanyahu publicly clashed with President Obama, saying Israel would not return to the 1967 borders which he described as "indefensible.""

vulnerable    unreasonable    inexcusable   

defensible   

undefendable   

indefensibility    indefensibly    indefensibleness   

unjustifiable    untenable    defenseless    insupportable    inexcusable    excuseless   

compensable    comprehensible    defensible    dispensable    indispensable    insensible    ostensible    reprehensible    sensible   

inadmissible    unsound    unwarrantable    unjustifiable    unacceptable    unconstitutional    untenable    valueless    justifiable    repugnant