indefensible vs. undefendable

[CarloSsS]

Can I use the word "undefendable" instead of "indefensible" in the following sentence? I know that "indefensible" would sound more natural, but is my version acceptable (albeit less often used) too?

I don’t care if you’d had too much to drink. Your behavior last night was quite undefendable.

 

[bhaisahab]

Can I use the word "undefendable" instead of "indefensible" in the following sentence? I know that "indefensible" would sound more natural, but is my version acceptable (albeit less often used) too?

I don’t care if you’d had too much to drink. Your behavior last night was quite undefendable.

It's not natural English.

 

[BobK]

You're right that it's more natural. COCA has 'indefensible' collocating with 'behavior' three times, and 'undefendable' never. BNC has 'indefensible' collocating with 'behaviour' once [I added the U, to make the comparison fair], and 'undefendable' never. So why not 'go with the flow'? ;-)

b

 

[CarloSsS]

So why not 'go with the flow'? ;-)

Let me tell you why. This was a part of a test in which I was given only a root of a word, in this case it was "defend", and then I had to derive a word that would fit the context using the given root. I used "udefendable" and wondered if it's acceptable. Sadly for me, it isn't.