Seven Hukum Sharii
1) Waajib : That which is obligatory upon the believer. The performance of such a deed merits reward, while neglect of this act merits punishment (in this life OR the Hereafter). Other terms synonymous with Waajib are - Fard, Laazim, & Muhattam (NOTE: in the Hanafi school, there is a technical difference between Waajib & Fard)
2) Haram : That which is expressly forbidden. The performance of such a deed merits punishment, while abstention from it merits reward.
3) Mandub : One is rewarded for such a deed if one performs it, however, one is NOT punished if one neglects to do it. Other term synonymous with Mandub are - Sunnah, Nawafil, 'Muraghab fi', and Mustahab.
4) Makruh : One is not punished for such a deed if one performs it, however, one IS rewarded for avoiding such a deed. That which is makruh, though it is not expressly forbidden, may lead to acts which are definitely haram and thus it is better to avoid them.
5) Mubah : One is not punished for acting upon such a deed, nor is one rewarded for performing such a deed.
The definition for these five can be found in the al-Maqasid of Imam an-Nawawi. Additionally we include -
6) Sahih : An act which according to all outward appearances (i.e. the fiqh of performing the action) seems to have been done correctly. An act classified as sahih is assumed to be acceptable, not taking into consideration the state of the person's heart, which Allah(TA) Alone knows for sure.
7) Faasid : An act which according to all outward appearances seems to have been done incorrectly. An act classified as faasid is assumed to be unacceptable, however due to the innocent ignorance of the person and purity of heart, it is possible that it may in fact be acceptable in the Sight of Allah(AWJ).