great, huge, large, substantial, vast
adequate, sufficient
low, small
existing
additional
last
It took my last reserves of strength and will to swim to the lifeboat.

untapped
The region is thought to have some of the world's largest untapped oil reserves.

hidden
She had hidden reserves of courage.

known, proven
proven oil reserves

capital, cash, currency, financial, foreign-currency, foreign-exchange, gold, international
In the face of a severe crisis relating to international reserves, the government devalued the currency twice.

dollar, sterling, etc.
coal, energy, fuel, gas, oil, petroleum (esp. AmE)
food
fat
The birds build up fat reserves to help them survive the winter.

have
We have only a small reserve of coal.

hold sth in, keep sth in, maintain
The crack troops were held in reserve behind the front line.

dig into (BrE), dip into, draw on, draw upon, tap, use
He had to draw on reserves of strength just to finish the race.

accumulate, build, build up, increase
deplete, exhaust
The company has depleted its reserves to make the purchase.

take

be available
dwindle, fall
rise

assets, currency, funds
requirement
tank
The plane was fitted with fuel reserve tanks for long-distance flights.

account
power

in reserve
The rail company has two trains in service and one in reserve.

reserve of
the world's reserves of oil

national
bird (BrE), forest, game, marine, natural, nature, wildlife

create, establish

deep
natural (esp. BrE)
They made him feel at ease, despite his natural reserve.

with reserve
Any contract should be treated with reserve until it has been checked.

without reserve
She trusted him without reserve (= completely).

play in (BrE)
He will continue to train and may play in the reserves next season.

side (BrE), team
goalkeeper (BrE), outfielder (AmE), striker (BrE), etc.
game, match (BrE)
role (AmE)
Bautista could be traded or moved into a reserve role.

air-force, army, marine, naval
strategic
volunteer

army, force, police
component, unit
officer, personnel, soldier, troops
duty