Step 1: Check each option against its standard spelling.
We compare every word to its accepted dictionary form.
Step 2: Analyse option (2).
"Multidisciplinery" is incorrect; the correct spelling is "multidisciplinary" (ending in -ary, not -inery). This is a common error due to the word's length.
Step 3: Verify remaining options.
"Assassination", "linguistic", and "refurbished" are all correctly spelled. Option (2) is the misspelled word.
\[ \boxed{\text{multidisciplinery}} \]