adjective
abortive
uh-BOR-tiv/əˈbɔːrtɪv/
Failing to achieve the intended result.
The archer lowers his bow after an abortive attempt to hit the target.

Etymology
The OED's analysis connects the base with being born “amiss.” Originally describing premature or stillborn offspring, abortive came to describe efforts that likewise fail to reach completion or a successful outcome.
In context
as you know the project was abortive and it's not entirely clear to me why in the end it it collapsed
More examples
- Several abortive negotiations preceded the agreement.
- The newspaper reported an abortive coup.
- His first abortive attempt taught him where the design failed.
Similar words
- unsuccessful
- Simply lacks success without necessarily ending prematurely.
- futile
- Suggests effort has little prospect of any useful result.