What is Fiendish?
1.
Devilish,spiteful,,frightening,alluring ,
The masked man said in a fiendish manner...
It was a fiendish place to look at...
The girl danced in a fiendish manner...
Grimly Fiendish...The Damned
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2.
Used to describe something (eg. an all-nighter) a bit mad/crazy/wicked etc. for various reasons, usually relating to alcohol/drug intake.
"did you see how many bennie's kel did last night?!!"
"yes! he had such a fiendish one the nutter!"
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3.
the way to be.
Did you see that girl? She was so fiendish i got a stiffy!
