i-adjective
Derogatory adjective describing someone or something as slow-witted, sluggish, or dim. Often used in casual, critical speech.
See also: とろい
あいつはとろくさいから、説明してもわからないよ。
That guy is so slow, even if you explain it he won't get it.
こんなとろくさいやり方じゃ、時間がかかりすぎる。
With such a sluggish method, it takes way too long.