Formula to find identical rows and display string elsewhere

[MossyPants]

I am looking for a way to find identical rows across three columns.
My worksheet looks similar to this:

I would like to find matching rows (A&B&C), and if there is a duplicate, I would like the word "Duplicate" to appear in that row in column D.
I hesitate to put any conditional formatting in columns A-C because they will be frequently copied&pasted into and out of, and I don't want to worry about messing up the formatting.
I'd like a formula for column D that would essentially remain invisible except to display the word "Duplicate" if necessary.
Ideal output:

I feel like COUNTIF might be what I need, but I can't quite figure out how to use it to do what I want.

 

[Peter_SSs]

You are likely to get much faster help if you give sample data and expected results in a form that helpers can copy yo test with. (XL2BB)

Try this in D2, copied down.

=IF(COUNTIFS(A$2:A2,A2,B$2:B2,B2,C$2:C2,C2)>1,"Duplicate","")

 

[MossyPants]

Huzzah! That's perfect.
Thanks so much!!

 

[Peter_SSs]

You're welcome. Thanks for the follow-up.

(Don't forget XL2BB next time )