てはいけないTidak boleh, Jangan

てはいけない expresses prohibition, meaning something 'must not' or 'cannot' be done. In contrast, なくてはならない expresses obligation or something that 'must' be done. These forms can be tricky for learners, as the negative form なくてはならない (literally, 'it's not good if you don't') means 'must,' while the affirmative form てはいけない ('it's not good if you do') means 'must not.'

てはいけない mengekspresikan larangan, dengan arti 'tidak boleh' atau 'jangan lakukan'. Sebaliknya, なくちゃ dan なきゃ adalah bentuk kasual dari なくてはいけない dan なければいけない yang mengekspresikan kewajiban, yaitu 'harus' melakukan sesuatu. Perbedaan keduanya ada pada tingkat kesopanan (formal dengan kasual) dan makna ('tidak boleh' dengan 'harus').

なくてはいけない mengekspresikan keharusan atau kewajiban, yaitu sesuatu yang 'harus' dilakukan. Sebaliknya, てはいけない berarti sesuatu yang 'tidak boleh' atau 'tidak dapat' dilakukan. Bentuk ini bisa membingungkan bagi pelajar: なくてはいけない terlihat negatif tetapi artinya 'harus' (secara harfiah: 'tidak baik kalau tidak [dilakukan]'), sedangkan てはいけない terlihat positif tetapi artinya 'tidak boleh' (secara harfiah: 'tidak baik kalau dilakukan').

てはいけない is used to express prohibition, meaning that something 'must not' or 'cannot' be done. In contrast, なければいけない expresses obligation, something 'must' be done. These forms can be tricky for learners, as なければいけない is negative in form but means 'must' (literally, 'it's not good if you don't'), while てはいけない is affirmative in form but means 'must not' (literally, 'it's not good if you do').

てはいけない is used to express prohibition, meaning that something 'must not' or 'cannot' be done. なければならない expresses the opposite meaning, i.e., that something 'must' be done. These forms can be tricky for learners, as なければならない appears negative but means 'must' (literally, 'it's not good if you don't'), while てはいけない appears affirmative but means 'must not' (literally, 'it's not good if you do'). (いけない and ならない themselves are essentially synonymous, though ならない is somewhat more formal/written-style.)

Both てはいけない and てはならない express prohibition, saying something 'must not' or 'cannot' be done. The two forms are equivalent in meaning, with the only difference being that ならない is slightly more formal and therefore more often found in the written language, such as in rules or regulations.

べからず and てはいけない are similar in that they both express prohibition, or the idea that you 'must not' or 'cannot' do something. The difference is in formality and how they connect to other words. べからず is a highly formal and archaic expression that nowadays is found mostly in regulations, proverbs, and so forth. It follows directly after the plain form of a verb, e.g. 入るべからず ('Do not enter.'). In contrast, てはいけない is far more common in the modern language, and connects to the て-form of verbs, e.g. 入ってはいけない ('You must not enter.')

てはいけない expresses prohibition, meaning something 'must not' or 'cannot' be done. In contrast, べきではない suggests that something 'should not' be done, often implying it's improper or that there's a better option. While both express negative recommendations, てはいけない is more authoritative and used for rules, whereas べきではない carries a more subjective nuance.

なくてもいい means something is optional; 'it's okay not to (do something).' In contrast, てはいけない expresses prohibition; 'you must not' or 'cannot' do something. For example, 食べなくてもいい means 'It's okay not to eat it,' while 食べてはいけない means 'You must not eat it.' The first gives freedom; the second sets a rule.