F

 Fall for (someone)  : To fall in love with someone

        He fell for her the moment he saw her.

Fall back (on) :To rely on something as a last resort or backup. 

               If I can't find a job, I might fall back on my savings. 

Fall in :To collapse inward or form a line or formation. 

         The old building finally fell in after years of neglect. 

Fall out:  a. To have a disagreement or argument

                    They fell out over a trivial issue and stopped speaking to each other

                  b. To unintentionally drop an object Her credit card fell out of her pocket.  

Fall through :To fail to happen or be completed as planned. 

                  Our plans to go on a trip fell through due to bad weather. 

Figure out :To understand or solve something       

        She finally figured out the solution to the puzzle. 

Find out: To discover or obtain information. 

               I need to find out what time the meeting starts. 

Full length :  extending to or showing the complete length

  1. a full-length mirror

  2. of the original length; not abridged

 Fill in (for someone)  : To do someone else’s job temporarily

Can you fill in for me while I’m on vacation?

Fall apart  : To stop working or break into pieces

The old chair fell apart when I sat on it.

Fall down  : To collapse or fall to the ground

     The little girl tripped and fell down the stairs.

Fall off  : To decline in quality or quantity

      Sales fell off during the holiday season.