also: ぱねえ
noun-modifying (irregular)
Slang abbreviation of 半端ない (hanpa nai). Used prenominally to express that something is extremely impressive or beyond ordinary. Very casual, often used by young people.
See also: 半端ない
あの選手のプレーはパネェ。
That player's performance is insane.
パネェ速さで走る車を見た。
I saw a car running at an incredible speed.
adverb
Adverbial use, emphasizing degree or quantity. Also slang abbreviation of 半端ない. Modifies verbs or adjectives.
昨日のテスト、パネェ難しかった。
Yesterday's test was ridiculously hard.
彼はパネェ食べる。
He eats an insane amount.
Also slang for 'amazing' or 'terrible', but パネェ is specifically derived from 半端ない and carries a nuance of being beyond ordinary limits.
Slang contraction of 半端ない (hanpa nai), with sound changes: ha-n-pa-na-i → pa-ne-e. The exact derivation is uncertain but widely accepted as a casual shortening.