interpreter:
(plural: ‘interpreters‘; pronunciation: the letter ‘i’ rhymes with the letter ‘i’ in “ink” — for the right pronunciation, please click here)

the Late Palestinian leader Yasser Arafat (L) and former US President Bill Clinton (R) exchanging views with the help of a renowned interpreter Gamal Helal (C)
a person who interprets;
a person who knows several languages (or at least two different languages) and helps people of different languages understand each other by telling each one the content of a conversation in their own language;
a person who uses his skills, such as art, music, poetry, etc., to represent something;
an advocate who represents someone else’s policy in a business deal;
a translator,

legal interpreter (centre) explaining legalities in a deal
The President of Ukraine and the President of Kenya discussed the political issues with the help of an interpreter., i.e. the President of Ukraine spoke in Russian and the President of Kenya spoke in Swahili — two different languages — and an official who knew both these languages explained the dialogues of Russian President to the Kenyan President in Swahili and the dialogues of Kenyan President to the Ukrainian President in Russian.
An artist who draws paintings of the sufferings of common man’ or ‘a poet who writes poems that show the plight of women’, etc. can also be called interpreters because they make us understand the sufferings of life in their the paintings or poems.
Mr Martin is the interpreter in the complicated business deal between our company and our supplier. i.e. in a business there are several law points that we do not know and Mr Martin, a qualified advocate, explains or points out these legalities to both of us so that we avoid the legal complications and make out a contract that is profitable to both of us.
Basically both these words are related to people who know more than one language and retell something from one language to another; and are most often used as synonyms. However, there is some difference between these two words: a translator is the one who rewrites (translates) a text, printed matter, from one language to another, e.g. a story written in English is rewritten in Arabic, usually word for word, by a translator, but an interpreter is the one who retells (interprets) some spoken dialogue in another language, e.g. when two people of different languages are engaged in a conversation — a Spaniard and a Korean — the interpreter listens to the expressions of the Spaniard and tells them in Korean to the Korean and listens to the expressions of the Korean and tells them in Spanish to the Spaniard. For an article that explains the difference between an interpreter and a translator, please click here.

interrupter (R)
An ‘interrupter’, on the other hand, is a person (or device/instrument) that stops or breaks some action. For example, “I was vexed with/at the interruptions while I was watching TV last night; the foremost interrupter was my little baby who cried for one thing or the other and I had to pacify him each time, and the other interrupter, the more annoying of the two, was my husband who kept on asking for one or the other of his things which he habitually chucks away once he’s done with them.”
