For the sentence, 你别乱闹. I think it means "do not randomly complain," but that doesn't sound right. I can't pinpoint what 乱 means.
乱 (adv): arbitrarily
on the basis of random choice or personal whim, rather than any reason or system.
without restraint in the use of authority; autocratically.
乱花錢 = spend money arbitrarily (randomly, without restraint)
乱闹 = arbitrarily (without reason, without restraint) making trouble
乱猜 = arbitrarily (randomly) guess
乱説 = arbitrarily (without reason, without restraint) say
乱 (adv) = 随意地/ 随便地(randomly); 武断地 (arbitrarily); 胡乱地 (indiscriminadamentely)
In 《现代汉语词典（第七版）》, one of the senses provided of 亂/乱 is
... 5. <副> 任意，随便 | at random, haphazardly
And in Wiktionary, we have this:
... 8. wildly; in an uncontrolled way; without order or reason; at random; haphazardly; having no direction or coherence; recklessly
亂說 / 乱说 ― luànshuō ― to say whatever is on one's mind
亂舞 / 乱舞 ― luànwǔ ― to dance in an unorganized, uncoordinated way
another way to say 乱闹 will be 胡鬧/胡闹 (Click to see the Wiktionary page).
这个词可不能乱用。 This word must be used in the proper way.
那个人在到处乱跑。 That person is running all over the place.