to try extremely hard to do something.

I was straining every nerve to catch what they were saying but they were sitting just a bit too far away from me.

• Fair's fair.
• fair shake
• fair to middling
• fair-weather friend
• fairy godmother
• fait accompli
• fall afoul of
• fall afoul of someone
• fall afoul of something
• fall all over
• fall all over to
• fall all over to do something
• fall all over yourself
• fall all over yourself to
• fall all over yourself to do something
• fall apart
• fall asleep at the switch
• fall back on
• fall back on something
• fall between two stools
• fall by the wayside
• fall down on the job
• fallen angel
• fallen idol
• fallen woman