In a manner characterized by flattery, excessive agreement, or fawning behavior to please others.
From 'assentator' (flatterer, from Latin 'assentator') + '-ily' (adverbial suffix). Latin 'assentari' means 'to agree with,' from 'ad-' (to) + 'sentire' (to feel). Over time, the meaning shifted to describe insincere agreement.
Latin writers like Cicero used 'assentator' to describe the courtiers and yes-men who surrounded powerful people—this adverb captures the exact tone of someone who agrees with everything you say, not from conviction but from desire for favor.
Complete word intelligence in one call. Free tier — 50 lookups/day.