reserves

civilians trained as soldiers but not part of the regular army
formality and propriety of manner
something kept back or saved for future use or a special purpose
an athlete who plays only when a starter on the team is replaced
(medicine) potential capacity to respond in order to maintain vital functions
a district that is reserved for particular purpose
armed forces that are not on active duty but can be called in an emergency
the trait of being uncommunicative; not volunteering anything more than necessary
hold back or set aside, especially for future use or contingency;
give or assign a resource to a particular person or cause;
obtain or arrange (for oneself) in advance;
arrange for and reserve (something for someone else) in advance;

reserves is a valid Scrabble (US) TWL word

reserves is a valid Scrabble Word in Merriam-Webster MW Dictionary

reserves is a valid Scrabble Word in International Collins CSW Dictionary

reserves is a valid Words With Friends word