Generous ↔ Mean
Generous
Happy to give money, time or help to others.
Arjun was generous and shared his lunch with everyone.
Mean
Not willing to give or share (British use).
He was too mean to buy anyone a cup of tea.
Stingy
Very unwilling to spend or give money.
Don't be stingy; buy enough sweets for the whole class.
Remember: In American English 'mean' usually means unkind, so 'stingy' is safer with international listeners when you mean 'not generous'.