Scots and Late Middle English

Feck (or fek) is a form of effeck, which is in turn the Scots form of effect. However, this Scots noun has additional significance:

* Efficacy; force; value; return
* Amount; quantity (or a large amount/quantity)
* The greater or larger part (when used with a
definite article)

From the first sense we derive feckless, meaning witless, weak or ineffective; worthless; irresponsible; indifferent; lazy.

Feckless remains a part of the Modern English and Scottish English lexicons; it appears in a number of Scottish adages:

"Feckless folk are aye fain o ane anither."
"Feckless fools should keep canny tongues."