狭い (semai) means "narrow" or "cramped." It's an い-adjective describing a small or restricted space, the opposite of "広い" (hiroi). It indicates a lack of space. For example, "この道はとても狭いです。" (Kono michi wa totemo semai desu.) means "This road is very narrow."

「狭(せま)い」は面(めん)積(せき)が小(ちい)さい時(とき)に使(つか)います。例(れい)：この道(みち)は狭(せま)いです。