The word is siesta (from Spanish).
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
The word afternoon is a noun, a word for the period of the day from noon to evening.Several dictionaries categorize 'afternoon' as an adjective; but only one, Oxford Dictionaries, categorizes 'afternoon' as an adverb. (eight dictionaries researched)
The word metalworking is one word.
One option is "afternoon".
eat, use
The word that works is idiot.
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.
Elevate
A walker is a pedestrian.
Traditionalist