It’s got to beeee PERFECT
(mushlam) complete, perfect
The root letters are ש-ל-מ. Words that derive from these root letters express שְׁלֵמוּת (shlemut) completeness, wholeness, perfection.
The word שָׁלֵם (shalem) means complete, whole.
(shalom) means peace.
Peace, as opposed to war, is something perfect and whole.
(hashlama) means acceptance; to לְהַשְׁלִים (le’hashlim) means to accept, make peace with something. Sometimes, you resist something, and only after a while you accept it. In this case, the last piece of your resistance falls away and you accept it and are at peace with the matter.
The word הַשְׁלָמָה also means to fill in or complete physically. An example of this can be a student who הִשְׁלִים (hishlim) completed all of his tests and requirements.
When you finish doing something, you say it is נִשְׁלַם (nishlam) completed, done.
When people take continuing education courses, they are doing a הִשְׁתַלְמוּת (hishtalmut). They are helping to complete or fill in their missing information or knowledge.