An adjective for something intense, but negative or undesirable.
Just as the word "intense
" is sometimes used as a pun to reference "camping", "a circus", "hippy sex", etc. (think: in tents), "entrencious" (in trenches) can refer to warfare, a drunken bum collapsed in the gutter, etc.
To emphasize the positive vs. negative connotation of these two words, merely consider the shape of a tent, which points up (^), and the shape of a trench, which points down (v).