Of, related to, or being a duplicate.

Is there such a word as duplicative?

involving duplication, especially unnecessary repetition of effort or resources: The report will highlight examples of wasteful or duplicative spending.

Is it duplicate or duplicative?

As adjectives the difference between duplicate and duplicative. is that duplicate is being the same as another; identical this may exclude the first identical item in a series, but usage is inconsistent while duplicative is of, related to, or being a duplicate.