Verb tell on has 2 senses
  1. denounce, tell on, betray, give away, rat, grass, shit, shop, snitch, stag - give away information about somebody; "He told on his classmate who had cheated on the exam"
    --1 is one way to inform
    Sample sentence:
    Somebody ----s somebody
  2. tell on - produce an affect or strain on somebody; "Each step told on his tired legs"
    --2 is one way to
    affect, impact, bear upon, bear on, touch on, touch
    Sample sentences:
    Something ----s somebody
    Something ----s something