Did you maybe mean one of these? rafting, rating, ratting, rethink
Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- n. Slang A person regarded as contemptible, obnoxious, or otherwise undesirable.
Wiktionary
- n. An informer or spy.
- n. A dislikable or contemptible person.
Examples
“Look, I'm a ratfink not to at least offer you breakfast, but I've got to get on this right away.”
“As I said above, I just called and let them know that I feel insulted every time that ratfink speaks.”
“Van Johnson plays John Alden in a rather small role, and a young Lloyd Bridges is the ratfink first mate.”
“He thinks Gadge deserved a metal for being the ratfink that he was.”
“He was recommended to me by my ratfink Mexican brother-in-law, whom I don´t get along with anymore, so that wouldn't help either.”
“You see what a vile little backstabbing ratfink Willard Mitt Romney really is...the French kindly help him to avoid an early death in the Mekong Delta and how does he repay them but with catcalls and brickbats.”
“And here's the checkered flag from that hot-rod daddy ratfink from another world - your pal, hyper dave AKA the datajunkie. posted by hyperdave at 5:12 PM”
“And under cover of the ongoing WH “shakeup”, Rove will probably leave before being either charged, or outed to all the world as a ratfink.”
“The ratfink Democrat is in the Senate, not the House, pal.”
“In my family, it was considered an insult to be called a fink and even worse to be called a ratfink.”
Lists
These user-created lists contain the word ‘ratfink’.
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Rats
rats, rat, tree-rat, pilori-rat, prorate, pro rata, Ratso Rizzo, ratfink, rat pack, Rat Pack, Rats!, rat race and 157 more...
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unkind words
unkind words or those refering them.
twit, gibe, blockhead, bonehead, cretin, dullard, imbecile, simpleton, clod, dunce, simp, ignoramus and 39 more...
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Unsavoury Types
insults, epithets, etc.
drotchel, drossel, drazel, flutch, lollard, scobberlotcher, ragabash, faineant, cad, buffoon, martinet, tosspot and 116 more...
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wunderkammer's Words
smarmy, bubkes, elucidate, togs, aeolian, carp, kibosh, bosky, ramshackle, mange, harpy, effervesce and 163 more...
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Animalia Wordia
Words or short phrases with animal names in them. Since I already have a dedicated list for 'monkey' words I shall leave them out of this one for the moment.
paper tiger, pigeon-hearted, lion-hearted, sacred cow, chicken heart, fraidy cat, scaredy-cat, snake oil, can of worms, snake pit, rat's nest, stool pigeon and 114 more...
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Words next
patrimony, cacophony, fearsome, coruscating, coruscating, coruscating, dolomite, dolorous, transdermal, chatty cathy, chatterbox, incessantly and 249 more...
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brin1d2lynn's list
Dooflobbie
Thingamajig
Hootendibbler
Whatchamacallit
Trifling
Mullish
Obstreperous
Impudent
Insolent
Crabby
Cranky
Idiocy
Hul...chagrinery, vexsome, irksome, carbuncle, cantankerous, splendiferous, odious, perfidious, parsimonious, pandemonium, mayhem, erstwhile and 59 more...
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R is for Red Clown
My R Words
rabble-rouser, rabblerouser, red clown, rabblerousing, ragamuffin, rama lama ding dong, rapscallion, rascal, ratfink, red herring, red rover, renegade and 39 more...
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Favourite Insults
wanker, bozo, crackpot, twerp, smarty pants, clodhopper, blackguard, frump, wimp, bumpkin, dick head, chump and 37 more...
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ye olde volcabulary
Words of a bi-gone era that I love.
rapscallion, flimflam, tomfoolery, bamboozle, buggery, hornswoggle, hoodwink, scalawag, smithereens, moxie, flibbertigibbet, rabblerouser and 15 more...
Tweets
Looking for tweets for ratfink.

reesetee Fink also once referred to a strike-breaker. From OED:
1926 Amer. Mercury Jan. 63/1 Dating from the famous Homestead strike of 1892 is the odious fink. (It) according to one version was originally Pink, a contraction of Pinkerton, and referred to the army of strikebreakers recruited by the detective agency. Oct 22, 2007
seanahan It is a combination of two similar insults. A rat refers to some spying or informing for the police, and fink means the same thing. You could combine either of these with stool pigeon, I suppose, but that would sound stupid. Oct 21, 2007
sonofgroucho Where on Earth does this word come from? Oct 21, 2007