Fed up and Low-down

Fed up adjective - Having one's patience, interest, or pleasure exhausted.

Low-down and fed up are semantically related In some cases you can use "Low-down" instead an adjective phrase "Fed up".

Low-down adjective - Not following or in accordance with standards of honor and decency.

Fed up and low-down are semantically related in depressed topic. Sometimes you can use "Fed up" instead an adjective phrase "Low-down", if it concerns topics such as discouraged.