noun

dereliction

dair-uh-LIK-shun/ˌderəˈlɪkʃn/

Serious neglect of an obligation or responsibility.

The lifeguard commits a dereliction of duty by ignoring a struggling swimmer.

A pool lifeguard ignores a visibly struggling swimmer while absorbed in her phone, making the failure of an assigned safety duty concrete.

Etymology

deLatinentirely

+reLatinback

+lictLatinleave

+ionLatinaction or state

Leaving something entirely behind supplies the central idea of abandonment. Applied to duty, this becomes neglecting or failing to carry out a responsibility rather than abandoning a physical thing.

In context

HowlRound Theatre Commons61:26

they told me if I filed a claim that I've been raped I'd also be charged with dereliction of Duty for leaving my weapon unattended

Helen Benedict's The Lonely Soldier Monologues—London—May 14, 2015

More examples

Failing to investigate the abuse reports was a serious dereliction of duty.
The board dismissed the director for repeated derelictions of duty.
Leaving the children unsupervised was a dereliction of her responsibility as their caregiver.

Forms

dereliction · derelictions

derelict adjective — Seriously neglectful of an assigned duty.

Similar words

neglect: Neglect covers inadequate care, whether or not a duty exists.
negligence: Negligence emphasizes a failure to exercise reasonable care.