ad·vo·cate 
(ădvə-kāt′)
(ădvə-kāt′)v. ad·vo·cat·ed, ad·vo·cat·ing, ad·vo·cates
v.tr.
To speak, plead, or argue in favor of: advocate a vegan diet. See Synonyms at support.
v.intr.
Usage Problem To act as an advocate: advocated for her patients; advocated for more stringent crime laws.
n. (-kĭt)
1. One that argues for a cause; a supporter or defender: an advocate of civil rights.
2. One that pleads in another's behalf; an intercessor: advocates for abused children and spouses.
3. A lawyer.
[From Middle English advocat, lawyer, from Old French advocat, from Latin advocātus, past participle of advocāre, to summon for counsel : ad-, ad- + vocāre, to call; see wekw- in the Appendix of Indo-European roots.]
ad′vo·cation n.
ad′vo·cative, ad·voca·to′ry (ăd-vŏkə-tôr′ē, ădvə-kə-) adj.
advo·ca′tor n.
Usage Note: The standard form of the verb advocate is transitive, meaning "endorse" or "argue for," as in The teacher advocated a new educational technique, which was accepted by 85 percent of the Usage Panel in our 2014 survey. Many readers balk when the verb is used to express the same meaning in an intransitive form with the preposition for: less than half (45 percent) of the Panel approved of The teacher advocated for a new educational technique. The intransitive is more acceptable, however, when the object of for is the beneficiary of the advocacy rather than the idea or action being advocated: two-thirds of the Panel approved The teacher advocated for her at-risk students. A careful writer will use transitive advocate in sentences indicating the idea or action, restricting the intransitive to sentences indicating the beneficiaries.