This kanji is composed of the narwhal and the construction radicals. The onyomi reading is sa; the kunyomi reading is hidari. The meaning of this character is left, as in, the opposite of right.
A basic example is saying I am left-handed, which is roughly like this:
Watashi wa hidari kiki desu.
…which is not really that basic after all since there is another kanji (利) in there that I completely know nothing of.
Ain’t I something? Haha.