Brown-Driver-Briggs
[
כִּיד]
noun [masculine] only suffix
כִּידוֺ Job 21:20, meaning unknown; read probably
מִּידוֺ his misfortune (as
Job 12:5 etc.)
כיד (√ of following; compare perhaps Arabic 
in sense labour, take pains, strive, or struggle with, 
war).
