The term 'SWIFT DESCENT' can be broken down into two words, 'SWIFT' and 'DESCENT'. The word 'SWIFT' is an adjective meaning 'moving or capable of moving with great speed', while the word 'DESCENT' is a noun meaning 'a downward slope or journey'. The crossword solution for this term is 'SWOOP', which is a verb meaning 'to fly or move suddenly and quickly in a downward direction'. Therefore, the term 'SWIFT DESCENT' can be defined as a sudden and rapid downward movement.