feckless

feckless \FEK-lis\, adjective:

1. Ineffective; having no real worth or purpose.
2. Worthless; irresponsible; generally incompetent and ineffectual.

He was a great admirer of the poetry of plain speech. He despised mere feckless adornments of language or thought.
-- Richard Elman, Namedropping: Mostly Literary Memoirs

Nelson spent decades in feckless pursuit of a superstructure for implementing his grand design.
-- Paul Andrews, How The Web Was Won

Grandpa was a jovial, good-natured man but feckless and addicted to drink, producing in Lucy an everlasting hatred of liquor that she must have drummed into her grandson.
-- Ron Chernow, Titan: The Life of John D. Rockefeller, Sr.

Feckless is from Scots feck, alteration of effect + -less.