half assed

(adjective) uninterested in something, unenthusiastic about something

Example Sentences:

Jeanette gave a half-assed effort on her presentation. I’d like her to do it again.

My best friend made a half-assed attempt to help me move into my new apartment.

From the Blogs:

Obama leaning toward half-assed plan of sending 34,000 more troops for Afghanistan

Media:

Similar idioms:

1. half-hearted
2. heart is not in something
3. half-baked idea
4. cover one’s half
5. get around