If you hired this lawyer to represent you in legal proceedings, and the end result was a monetary award that you won in the case, most likely the lawyer collected the award in it's entirety. Then send you the remainder after deducting their legal fees. That lawyer is required to send you a 1099-MISC, and to do that you are required to provide the information being requested by the lawyer, on the W-9. If this is the case and you don't provide the information, the IRS will fine you quite heavily. So get this done ASAP, as the lawyer has until Feb 15th to file that 1099-MISC with the IRS. You make him late, you pay the late penalties.
https://www.irs.gov/pub/irs-pdf/i1099msc.pdf page 2-3 regarding payments to attorneys where you may have to issue them a 1099.
Attorneys' fees of $600 or more paid in the course of your trade or business are reportable in box 7 of Form 1099-MISC, under section 6041A(a)(1). Gross proceeds paid to attorneys. Under section 6045(f), report in box 14 payments that: Are made to an attorney in the course of your trade or business in connection with legal services, but not for the attorney’s services, for example, as in a settlement agreement; Total $600 or more; and Are not reportable by you in box 7. Generally, you are not required to report the claimant's attorney's fees. For example, an insurance company pays a claimant's attorney $100,000 to settle a claim. The insurance company reports the payment as gross proceeds of $100,000 in box 14. However, the insurance company does not have a reporting requirement for the claimant's attorney's fees subsequently paid from these funds.
These rules apply whether or not: The legal services are provided to the payer, The attorney is the exclusive payee (for example, the attorney's and claimant's names are on one check) and even if, Other information returns are required for some or all of a payment under section 6041A(a)(1). For example, a person who, in the course of a trade or business, pays $600 of taxable damages to a claimant by paying that amount to a claimant's attorney is required to:
Furnish Form 1099-MISC with box 7 completed to the claimant under section 6041, and Furnish Form 1099-MISC with box 14 completed to the claimant's attorney under section 6045(f). For more examples and exceptions relating to payments to attorneys, see Regulations section 1.6045-5.
However, these rules do not apply to wages paid to attorneys that are reportable on Form W-2 or to profits distributed by a partnership to its partners that are reportable on:
Schedule K-1 (Form 1065), Partner's Share of Income, Deductions, Credits, etc.; or
Schedule K-1 (Form 1065-B), Partner's Share of Income (Loss) From an Electing Large Partnership.
Payments to corporations for legal services. The exemption from reporting payments made to corporations does not apply to payments for legal services. Therefore, you must report attorneys' fees (in box 7) or gross proceeds (in box 14) as described earlier to corporations that provide legal services.