swear and curse                   These two words basically mean the same thing: say strong words and expressions (usually of four letters) when someone feels frustrated.

gristle                                     part of meat which is inedible                                 

jolly rotten                              very, very bad (rotten is the third form of the verb 'rot', which is a kind of decay typical of fruit and vegetables)

feeling in the dumps             feeling sad and hopeless

chump                                     stupid person

purse your lips and whistle        keep your lips together and blow the air through them to make a high-pitched sound. Like this:



        Picture from here


grin                                          very broad smile that shows the teeth   

                                                                 
the grin of a cat (from here)


terminal breath                      the last breath in somebody's life

the last laugh is on you         you are the one who laughs last