아/어/여라 is an imperative ending suffix. 그만하(다) + 여라 => 그만하여라 => 그만해라 그만해 used when an a person giving order to younger than or the same age as the speaker. 그만해라 used when an elder person giving order to younger person. Quoted from http://www.howtostudykorean.com/unit-2-lower-intermediate-korean-grammar/unit-2-lessons-34-41/lesson-40/#402 Imperative mood: Verb stem + ~아/어(요) The easiest (and least formal) way to give a command in Korean is simply by adding ~아/어 to a verb stem. For example: 밥을 천천히 먹어 = Eat your food slowly 열심히 공부해! = Study hard! You can use this form when you are giving a command to somebody who is younger than you or the same age as you, or somebody who you are close with. Saying something like “빨리 가!” to your superior would most likely warrant a slap in the face. Imperative mood: Verb stem + ~아/어라 Another way to give a command in Korean is by adding ~아/어라 to a verb stem. The formality is similar to the ~아/어 form you learned previously. Some examples: 빨리 가라! = Go fast! 그렇게 해라! = Do it like that 내 말을 들어라 = Listen to what I say 밥을 먼저 먹어라 = Eat (rice) first (you can eat first) However, the ~아/어라 form is generally used by much older people (parents or grandparents) when they are giving orders to younger people. As I said, the formality is very similar (if not the same) as using ~아/어, but I would much prefer to use ~아/어 over ~아/어라. One time I said something to my girlfriend like “가라” and she just laughed and said “Who are you? My grandfather?”