the.com/ineptitude

means A lack of skill or fitness for the task at hand — not knowing what you're doing, and often not knowing that you don't know.

from From French ineptitude, from Latin ineptitudo, built on ineptus — 'in-' (not) plus 'aptus' (fit, suitable, apt). So an inept person is, quite literally, the opposite of apt: unsuited, unfitted, out of tune with the task. The Latin aptus also gives us 'adapt' and 'adept' — making ineptitude the dark twin of competence, sharing the same root family but none of the skill.