One option is the word speechless.
loss of memory is called as amnesia
Amnesia
The noun (used as plural) is condolences.
There is no one-word substitute in English for "son-in-law."
The word you want is florist.
Sportsmanship is a word substitute for spirit of game
One of them is earwax.
The word metalworking is one word.
eat, use
One possible substitute for "their" is "his" or "her" depending on the gender of the person/people being referred to. Another substitute can be "its" when referring to a non-human object or entity.
The word that works is idiot.
The word is "cram" which means to pack or compress tightly, which is used metaphorically to mean trying to force a large volume of information into your short-term memory.
Elevate
A walker is a pedestrian.