他人の陰口をきいてはいけません。

another person; other people; others; unrelated person (i.e. not related by blood); outsider; stranger

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

malicious gossip; backbiting; speaking ill behind someone's back

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

apprehension; uneasiness

if ... then; when; and; why don't you...?; the more (one does something); because; since