A while back I was reading the back of a book when the word indefatigable appears, being a rudimentary scholar I had to look it up. I decided to just put defatigable, some dictionaries acknowledge this - and fatigable - as a word whilst other dictionaries such as this do not. Is it proper for use or not? (Right now my Mozilla spell-checker is showing them as incorrect spellings.)

Lexical specimen in dire question here “defatigable” = probably back formation of standard Eng. adjective “in~” and so even more neologic “fatigable” by exact same process from said previous development “defatigable” but check lumbrous ‘n’ cumbrous OED for specific times & dates regarding all, if any, forms submitted herein and be forever prepared to explain yourself when coining such novel vocabulary!

Lumbrous and cumbrous.  I like that!

Lexical specimen in dire question here “defatigable” = probably back formation of standard Eng. adjective “in~” and so even more neologic “fatigable” by exact same process from said previous development “defatigable” but check lumbrous ‘n’ cumbrous OED for specific times & dates regarding all, if any, forms submitted herein and be forever prepared to explain yourself when coining such novel vocabulary!

Hmmmm! Seems somewhat repititious from above. But probably the comment needs to be made, be it lumbrous ‘n’ cumbrous, or simply repitition is the mother of learning.

"Fee, fi, fo, fum"—methinks I smell the all too familiar blood, sweat & tears of yet another over-worked, under-paid instructor of the English language!

.....and what is the odour of your profession, O Fragrant Baboon?