To ask Her Majesty's Government what is their definition of (1) man, (2) woman, (3) male, (4) female, (5) boy, (6) girl, (7) transgender, (8) sex, (9) gender, and (10) gender identity.
In the Equality Act 2010, "man" is defined as "a male of any age"; and "woman" as "a female of any age". The other terms listed in the question are not defined, except that "the protected characteristic of sex" is defined in Section 11 of the Equality Act as a reference to a man or a woman, or to persons of the same sex, as appropriate.
The Government Equalities Office provided a list of terms to help set the context and support respondents in completing the 2018 Gender Recognition Act Consultation. This included short descriptions of the terms ‘sex’, ‘gender’, ‘transgender’ and ‘gender identity’: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/721725/GRA-Consultation-document.pdf