亏空 functions both as a noun ('a deficit / shortfall') and as a verb ('to be in deficit / fall short'). Common collocations:
弥补亏空 'make up the shortfall',
出亏空 'incur a deficit'. The second character
空 is read with neutral tone here (kong, not kōng) in most native pronunciation, though dictionaries also list kuīkōng. Compare
赤字 (chìzì, 'red ink / deficit') which is the more bookkeeping-formal term.
