Complexify is a modern formation from complex + -ify, modelled on simplify. Complex derives from Latin complexus ('entwined'), from complecti ('to entwine, embrace'). The historical trail runs through complexus in Latin and plectere in Latin. Morphologically, complexify is transparent: a modern formation from complex + -ify, modelled on simplify. Used as a verb, complexify now means "make or become more complex", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in derived forms such as complexification and related forms such as complex, complexity, and complexness. The result is a borrowed or transmitted form whose modern spelling carries a compact record of its route into English.