Examples
“She, like nObama, believe what that crazy old Anti American, black liberation preachin whacko believes, it's just that simple.”
“Another whacko from the reichwingnuts in the deliverance wing of the fascist GOP.”
“No wonder the poor pathetic whacko is still single.”
Think Progress » Alito: Those Weren’t My Personal Views, I Was Just Lying To Get A Job
“Anyone that quotes that is another Opus Dei cult whacko from the clique of MizzWrong.”
Think Progress » From “Mission Accomplished” to “Tough Days Ahead”
“Unbelievably naive, and I would agree with "whacko"--and I've met a few people who actually seem to believe that.”
“I will be honest and say I am pretty liberal in my views (which I won't defend here and simply say I didn't vote for the current set of elected officials), and say that until there comes a time where we can guarantee that I can get on a plane/bus/transportation device and ensure that some whacko is not on there with a grudge or whatever - I am willing to sacrifice my "right" to carry those items.”
“We’re in whacko territory now with this administration and its supporters.”
“If they are indeed whacko, that isn't a problem and they should be allowed on the ballot.”
“I finally gave up posting there as I was afraid anyone who saw it would think that I am a bizarre whacko, which is quite possibly true, as you might notice from the final post....”
“I mean, when he teamed up with Lenora Fulani, for instance, someone who's made a lot of anti-Semitic statements in the past, and their sort of political union was covered as just another news event rather than Pat Buchanan teams up with discredited whacko, which is much more accurate I think, yeah, that's incomplete news coverage.”
Lists
These user-created lists contain the word ‘whacko’.
-
Bonkers
crackers, barmy, half-baked, mental, unhinged, barking, cuckoo, cracked, nuts, mad, insane, touched and 24 more...
-
jmjarmstrong's list
Words that I used to know.
geloscopy, hunker, willy nilly, harum scarum, whacko, meh, nork, misunderestimate, atrabiliousness, luftmensch, auxanometer, hyperhedonia and 1948 more...
-
Cloudstreet
From Cloudstreet by Tim Winton. Expect lots of new-to-me words and/or just pleasing words encountered in this book, perhaps mostly Australian slang.
chiack, staggerjuice, thunderbox, patterson's curse, cactus, dreckly, compo, hayburner, mulie, carn, dag, grizzle and 34 more...
Tweets
Looking for tweets for whacko.

knitandpurl "From his gladstone bag the stranger takes a bottle and a loaf of white bread.
Whacko, says Quick.
The black man pulls him off a hunk of bread and Quick takes it. Then the bottle."
Cloudstreet by Tim Winton, p 209 of the Graywolf Press hardcover edition Apr 1, 2010
jmjarmstrong JM often rushes outside and cries 'whacko!' and sometimes even 'whacko-the-diddle-o!' Feb 1, 2009