Meaning of SIMPLE in English
(NO MORE THAN) [adjective] [before noun; not gradable] - without anything more or otherI didn't break the window - that's the simple truth.We didn't go swimming for the simple reason that the water was too cold.The simple fact is that you're late and we've missed the start of the show.Simple interest is money that is paid only on an original amount of money that has been borrowed or invested, and not on the additional money that the original sum earns.Compare compound (COMBINATION).A simple fracture is one in which the broken bone does not go through the flesh. Compare compound fracture at compound (COMBINATION).
Cambridge English vocab. Кембриджский английский словарь. 2012