to put in a half assed effort at something, but complete it. Often pertaining to work which is complete and pretending to have worked a long time on, when in fact little to no effort was put into it. Derived from deciding to not physically attend a meeting in, but rather to be present by phone only.
Even though he had a huge project due Friday, he went to a party and got hammered Thursday night. He totally phoned it in.
(verb) to have completed an action, especially giving a performance, while showing a minimum of effort.
Generally used to refer to performances that border on unprofessional. The intended audience would have been similarly disappointed if the person had delivered the performance by speakerphone, in order to spend more time on leisurely pursuits.
"Her song and dance routine at the music awards was horrible! She looked out of shape, she forgot half the words... she basically just phoned it in."
Being generally lazy with a task. Doing it half-assed instead of with your full ass.
Guy 1: Did you watch the last season of the O.C.?
Guy 2: It sucked.
Guy 1: Yeah, they really phoned it in on that one. They just kept killing people off and making up new characters.
Man 1: I phoned it in on work on friday. I basically did nothing all day but eat a sandwich.