slap on the wrist vs telling-off

slap on the wrist

• An overly mild punishment; a reprimand. 

• Used other than figuratively or idiomatically: see slap, wrist. 

• To punish in an overly mild and largely symbolic manner. 

• Used other than figuratively or idiomatically: see slap, wrist. 

telling-off

• An instance of telling someone off, a reprimand or scolding.