Related Clues:

• Narrow space
• Space between peaks
• Trendy clothing giant
• Tribute to the government
• Word with "luxury" or "excise"
• VAT or DIRT, say
• See 15
• Payment to the Exchequer
• Strain - duty
• Space (maybe for a year?)
• Income __
• Generation separator
• Reason for braces, perhaps
• Wage earner's payment
• Test to the max