deficiency / deficit / luckily / it's lucky that... / (often ironically) fancy that...
亏
=
二
+
㇉
:
Mnemonic symbol: a lucky leprechaun. The leprechaun (亏) wants to propose to Karl Koala (ku) and uses the romantic moment in front of the Eiffel Tower (ei1). Unfortunately he has no ring, so he uses a capacitor (二) of which he bent the legs to build a ring. He's quite lucky (亏), because right after he gives the ring to Karl, a lightning bolt (㇉) strikes and hits poor Karl Koala. Had the leprechaun kept the ring, the lightning bolt would have hit him instead.