Akademik

много на себя брать
МНОГО НА СЕБЯ БРАТЬ/ВЗЯТЬ coll, rather impol when addressed to the interlocutor
[VP; subj: human]
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to overestimate one's capabilities, exceed the limits of one's authority, act in a way one has no right to etc:
- X много на себя берёт{{}} X is biting off more than he can chew;
- X is taking on more than he can handle;
- X is getting in over his head;
- X is going too far;
- [in refer, to one exceeding one's authority] X is (way) out of line;
- X is overstepping his bounds.
     ♦ ...[Я] взвалил его [баллон] на плечо... Пройдя первые десять ступенек, я понял, что слишком много взял на себя. Лет пять назад я мог пройти с таким баллоном втрое больше, теперь это было мне не под силу (Войнович 5). ...I hefted the cylinder up on my shoulder. ...After the first ten steps I realized that I'd bitten off more than I could chew. Five years ago I could have carried a cylinder like that three times as far, but now it was too much for me (5a).
     ♦ [Нина:] [Мой жених] волевой, целеустремлённый... Много он на себя не берёт, но он хозяин своему слову. Не то что некоторые (Вампилов 4). [N.:] He's [my fiancd is] headstrong and purposeful. ... He won't take on more than he can handle, but he's as good as his word. Not like some... (4a).

Большой русско-английский фразеологический словарь. — М.: ACT-ПРЕСС КНИГА. . 2004.