placid
adj.
1620s, from French placide (15c.) and directly from Latin placidus "pleasing, peaceful, quiet, gentle, still, calm," from placere "to please" (see please). Related: Placidly; placidness.
〔李〕[plac;-ida.] a.平静的； 宁静的； 温和的 ←plac,pleas (L placere)=to please 取悦，使高兴
〔李〕a. 平静的，温和的 [plac =to please] ←-id [L] 表示“有⋯性质的”