complication
Concise Oxford English Dictionary © 2008 Oxford University Press:
complication/kɒmplɪˈkeɪʃn/
▶noun
- 1 a circumstance that complicates something; a difficulty.
■ a confused or complex state.
- 2 Medicine a secondary disease or condition aggravating an already existing one.
'complication' also found in these Oxford entries:

