a frugal farmer.
a frugal lunch.
a sparing father and a spending son.
an economical meal.
an economical shopper.
foil your opponent.
Scots Gaelic.
sparing in their use of heat and light.
stinting in bestowing gifts.
the Scots community in New York.
thrifty because they remember the great Depression.
What ultimately frustrated every challenger was Ruth's amazing September surge.
`Scotch' is in disfavor with Scottish people and is used primarily outside Scotland except in such frozen phrases as `Scotch broth' or `Scotch whiskey' or `Scotch plaid'.
`scotch' is used only informally.
`Scottish' tends to be the more formal term as in `The Scottish Symphony' or `Scottish authors' or `Scottish mountains'.