admonisher

1. To reprove gently but earnestly.

2. To counsel (another) against something to be avoided; caution.

3. To remind of something forgotten or disregarded, as an obligation or a responsibility.

Synonyms: These verbs mean to correct or caution critically. Admonish implies the giving of advice or a warning in order to rectify or avoid something: "A gallows erected on an eminence admonished the offenders of the fate that awaited them" (William Hickling Prescott).
Reprove usually suggests gentle criticism and constructive intent: With a quick look, the teacher reproved the child for whispering in class.
Rebuke and reprimand both refer to sharp, often angry criticism: "Some of the most heated criticism . . . has come from the Justice Department, which rarely rebukes other agencies in public" (Howard Kurtz). "A committee at [the university] asked its president to reprimand a scientist who tested gene-altered bacteria on trees" (New York Times).
Reproach usually refers to regretful or unhappy criticism arising from a sense of disappointment: "Every other author may aspire to praise; the lexicographer can only hope to escape reproach" (Samuel Johnson).