Sure, here is the definition of the word “expense”:

Expense: A sum of money spent for a particular purpose or to cover a particular cost.

Examples:

• The company had a total expense of $10,000 for the quarter.
• My personal expenses this month were $500.
• The government has a high expense for defense.

Synonyms:

• Cost
• Expenditure
• Liability
• Outlay
• Burden

Antonyms:

• Income
• Revenue
• Gain
• Surplus
• Credit