(politics) A Member of Parliament who does not have cabinet rank, and who therefore sits on one of the backbenches or in one of the back rows of the legislature.

plural of backbencher

relating to the back benches in parliament / Pertaining to the preparation of a donor organ prior to transplantation. / Secondary or inactive.

(politics, UK, New Zealand, often attributive) In a house of legislature following the model of the Westminster system (such as the UK House of Commons), any bench behind either of the front benches and occupied by rank-and-file members.

plural of backbench