phone it in

phone it in AND fax it in (to do sth without making much effort) — халтурить, схалтурить в чем-л; выдавать халтуру; работать кое-как, не в полную силу, халтурно

Example 1: Cruise is totally phoning it in in this new release.

Example 2: The show was OK. The singer was kind of phoning it in though.

Example 3: Her performance was phoned in.

Example 4: An unimaginative and humourless dark comedy from French director Luc Besson, starring Robert De Niro who appears to be phoning his lines in.

Used to talk about concerts, movies, sports competitions. It can also be used to talk about other types of performances, like you’re performance at work. If you knew you were going to quit your job for months before you did, and you stopped trying very hard, you could say you were phoning it in near the end.

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The meaning of 'to do sth without much effort' is relatively recent, and comes from American English, despite the fact that phone is used much less in AmE than BrE. It implies that someone’s performance is so poor or lacking in conviction that it is as if they were not there at all, but just stayed at home -- the image is a person phoning rather than actually showing up. It is used especially in the phrase phone it in, and variations include fax it in:

Example: He didn’t phone in the performance, he faxed it. The audience should have asked for their money back.

see also
[халтура]
[кое-как]