Done quickly, without taking care or interest. (Cambridge Dictionary)
Characterised by routine or superficiality: Mechanical. (Merriam – Webster)
Lacking in interest or enthusiasm. (Merriam – Webster)
A perfunctory action is done quickly and carelessly, and shows a lack of interest in what you are doing. (Collins Dictionary)
(of an action) carried out without real interest, feeling, or effort. (Oxford Dictionaries)
Work School English. Perfunctory.