Feckless

/ˈfɛkləs/

adjective

lacking initiative or strength of character; irresponsible

The word 'feckless' comes from the Scottish dialect word 'feck', meaning 'effect' or 'value'. So, 'feckless' literally means lacking value or effect, hence the idea of someone being ineffective or irresponsible.

His eyes lost their menacing cast (they were bottlegreen, and how could such clear and feckless eyes have seemed menacing, or even dark?).

King, Stephen

The Stand

Now look, this is our Caspar, feckless Caspar, returned from the Hague.

Gregory Maguire

Confessions of an Ugly Step Sister

Aeron Greyjoy had been the most amiable of his uncles, feckless and quick to laugh, fond of songs, ale, and women.

George R. R. Martin

A Clash of Kings

They were incorrigibly children of the idea, feckless and colour-blind, to whom body and spirit were forever and inevitably opposed.

T. E. Lawrence

Seven Pillars of Wisdom