This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form visually contains 忄 (heart) and 弱 (weak), but the original component relationship is unclear.
The left side is the heart radical 忄, and the right side is 弱 (weak). Picture a weak heart that is uncertain and anxious, but remember the actual meaning is unclear.
For デキ, imagine a weak heart that needs a daily dose of digitalis: 'deck' of cards with a heart symbol -> デキ, but the heart is weak.