To deduct (an amount in withholding tax) beyond the tax owed. (verb-transitive)
To subject to overwithholding. (verb-transitive)
To deduct too much withholding tax. (verb-intransitive)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "overwithhold" in a sentence
"She tries to overwithhold all year long in order to ensure a larger refund; this year, it will be $1,600."
"But he has younger family members who overwithhold on purpose."
"It's OK to overpay your federal estimated tax (or to overwithhold)."