Ingratiate is a verb that means to bring oneself into favor with.
The Latin phrase in gratium (een GRATS ee oom) means ‘in favor.’ When someone ingratiates themselves to someone, they bring themselves in favor with them. The word is frequently used in an unflattering way to suggest that the person doing the ingratiating has an agenda.
When Harvey offered to work late last week, we knew he was simply trying to ingratiate himself to the new boss. This was exactly what we’d come to expect from a man who has a history of trying to kiss up to people in authority.