extraneous duty allowance vs special duty allowance

extraneous duty allowance and special duty allowance both are nouns.

Word	Noun	Adjective	Verb	Adverb
extraneous duty allowance	Yes	No	No	No
special duty allowance	Yes	No	No	No

As nouns, extraneous duty allowance and special duty allowance are synonyms defined as:

extraneous duty allowance and special duty allowance: an allowance payable to employees who are given special assignments or perform additional duties.

Other synonyms of extraneous duty allowance include extra duty allowance.

extraneous duty allowance (noun)	special duty allowance (noun)
an allowance payable to employees who are given special assignments or perform additional duties.	an allowance payable to employees who are given special assignments or perform additional duties.