Here are some synonyms to help you understand its meaning:
* Routine
* Mechanical
* Superficial
* Half-hearted
* Automatic
* Listless
Examples:
* "She gave a perfunctory wave to her neighbors as she rushed by."
* "The students answered the teacher's questions with perfunctory nods."
* "The doctor conducted a perfunctory examination, barely looking at the patient."
Essentially, it describes an action done without any real thought or effort, just to get it over with.