Priberam, the dictionary reproduced in the question, lacks a couple of common meanings of macacada. I list all of them below, so we can have them all in one place. These are based on Aulete digital, Infopédia, Dicionário da Academia das Ciências de Lisboa, and native speaker's experience. Numbers are not in order, so that they correspond to numbers in the question, and meanings are in a logical sequence.
(1) Bando de macacos — troop of monkeys — also macacal, macacaria.
(4) Grupo de pessoas grotescas ou ridículas — group of grotesque or ridiculous people — also macacal.
(2) gesto ou trejeito próprio de macaco; trejeito grotesco — grotesque or monkey-like gesture or grimace — also, perhaps more commonly, macaquice.
(3) ato de imitar grotesca ou ridiculamente alguém — the act of grotesquely or ridiculously imitating somebody — also macaquice.
(5) ato ou comportamento disparatado e brincalhão — silly and playful act or behaviour — also macaquice or palhaçada (from palhaço, clown).
(6) situação ridícula; espetáculo sem qualidade — ridiculous situation; poor-quality show — also palhaçada.
(7) (Brazil) grupo de amigos, companheiros, familiares – group of friends, relatives.
(8) Phrase: (Portugal) o fim da macacada grande confusão ou descontrolo; que provoca irritação em alguém importante, como o patrão, mãe, ou esposo, gerando problemas — great confusion and lack of control; that irritates somebody important, such as the boss, mother, or spouse, raising trouble.
Now, your sample sentences. I’ve never heard of “chimp-martialing” anybody either, but the translation, suggesting "court-martial," sort of conveys the original meaning. O fim da macacada can mean different things, but “insubordinate behaviour” is likely to cause a very angry reaction from someone in a position of power (that’s one type of fim da macacada), which may well get you “chimp-martialed”. I suppose you could also say:
You carry on with your insubordinate behaviour, and all hell will break loose.
The second sentence is vaguer, because meanings (5) and (6) fit, and (6) is by itself quite broad. The macacadas you’re growing weary of could refer to a friend trying to be funny, or disorganisation at your work place, members of parliament acting up, or a theatre play. “Monkeyshines,” because it suggests pranks and mischief, might apply to your friend but maybe not to the other situations. “Monkey business” would probably be a better fit; or “nonsense”; or “circus”.
The real meaning in English, of what?... of the word macacada?Since the question's title asks it directly I thought people would understand, I'm sorry if it wasn't clear enough. Was that the reason for the downvote?