The people in my office are putting out a curse-jar. Because I’m both a wise-ass and stingy, I need as many dirty-soundings words or phrases as I can get.
So far all I have are:
Wankel Rotary Engine
Cunning linguist
Bolshevik
I now turn to you all.
Uvula
Masticate
Origami
Funk and Wagnalls
Frigate
Circumspect
kumquat
thespian
Flocculate.
Cogitate .
Banker.
Angina.
You masticating thespian! (A favorite at snack time in the theater.)
In honor of another thread:
Slanket.
Mastoid. A bone behind the ear.
Yonkers, a city in New York.
Caulking gun
The first thing that came to mind when I read the thread title.
Fuquay-Varina (bonus: spellcheck tries to change Varina to Vagina)
and of course the Fuqua School of Business
Homo erectus
Heh
Australopithicus sounds pretty bad, too.
Lots of good architectural ones. Quincunx. Squinch. Lesbian cyma. Opistodomus.
Also good ones in bike mechanicking. Nipple wrench. Seat tube reamer. Head tube reamer. Bottom bracket reamer.
Wait, now – the OP wanted words that *sound *dirty, but aren’t, not the other way around! 
For mine, may I suggest Master Debater, weenus, homozygotic and sheep dip?
Widdershins !!! (My SO actually said this to me … fortunately I already KNEW what it meant 
Deosil !!! I replied
Learned these from another SDMB … 
non-dairy creamer
Matriculate
abreast
Anything can sound dirty if you try hard enough…
“I’m getting urges in my areas…”