ring (or call or phone) someone back means return a phone call (e.g. I’ll ring back later.) 
ring out means make a sudden loud sound (e.g. When a sound rings out, it is loud and clear.)

rip somebody off means to remove something very quickly, or cheat somebody, or charge excessively or obtain money unfairly (e.g. This government is ripping off the country. Tourists are worried they’ll get ripped off a lot when they don't speak the language.)

rip up means to tear something into small pieces, or stop using it (e.g. The boss ripped up all my reports. I have to just rip up reports and start again.)

run away means leave, escape (e.g. Marry ran away to avoid a forced marriage from home and has been missing for three days.)

run into somebody/ something means meet unexpectedly (e.g. I ran into an old school-friend at the mall. The company ran into some financial problem and needed to borrow some money immediately.)

run out (of something) means used all or to finish of something (e.g. We ran out of petrol on the motorway. I must renew my passport because it will run out next month.)

run over something means explain quickly, or exceed a time limit, or rehearse, review (run through) (e.g. Ann ran over her notes before giving the lecture. Let's run over/through presentations one more time before the meeting.)