This is the 3471st most frequent Russian word.
простой
Simple.
'простой' is used as an adjective describing 'пример', meaning 'simple' or 'straightforward' in this context.
Это простой пример.
This is a simple example.
'простой' describes 'человек', emphasizing the person's ordinary or common nature.
Он был да разве не простой человек.
Wasn't he but a common man?
'простой' is declined to match 'словами', showing its role as a descriptive adjective meaning 'uncomplicated' or 'clear'.