POWER OF ATTORNEY

        Know all by these presents, that the undersigned hereby constitutes and
appoints Jason Krantz, Richard Booth and David Samuels of Definitive Healthcare
Corp. (the "Company") or any of them signing singly, and with full power of
substitution, the undersigned's true and lawful attorney-in-fact to:

        1.   prepare, execute in the undersigned's name and on the undersigned's
             behalf, and submit to the U.S. Securities and Exchange Commission
             (the "SEC") a Form ID, including amendments thereto, and any other
             documents necessary or appropriate to obtain codes and passwords
             enabling the undersigned to make electronic filings with the SEC of
             reports required by Section 16(a) of the Securities Exchange Act of
             1934 or any rule or regulation of the SEC;

        2.   execute for and on behalf of the undersigned with respect to the
             Company, Schedules 13D and 13G and Forms 3, 4, and 5 in accordance
             with Sections 13 and 16(a) of the Securities Exchange Act of 1934
             and the rules thereunder;

        3.   do and perform any and all acts for and on behalf of the
             undersigned which may be necessary or desirable to complete and
             execute any such Schedules 13D or 13G or Form 3, 4, or 5, complete
             and execute any amendment or amendments thereto, and timely file
             such form with the SEC and any stock exchange or similar authority;
             and

        4.   take any other action of any type whatsoever in connection with the
             foregoing which, in the opinion of such attorney-in-fact, may be of
             benefit to, in the best interest of, or legally required by, the
             undersigned, it being understood that the documents executed by
             such attorney-in-fact on behalf of the undersigned pursuant to this
             Power of Attorney shall be in such form and shall contain such
             terms and conditions as such attorney-in-fact may approve in such
             attorney-in-fact's discretion.

        The undersigned hereby grants to each such attorney-in-fact full power
and authority to do and perform any and every act and thing whatsoever
requisite, necessary, or proper to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the
rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming any of the
undersigned's responsibilities to comply with Sections 13 and 16 of the
Securities Exchange Act of 1934.

        This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 13th day of August, 2021.


                                        By: /s/ Jason Krantz
                                        ----------------------------------------
                                        Name: Jason Krantz