person who has a suitable ability

technician

qualified; suitable for some purpose; meeting standards or requirements

one who is qualified; that which is suitable

enemy ranks

application of something

drop

foolish; stupid / (historical) Lu (state) (vassal state during the Zhou Dynasty of ancient China) / (dated) short form for Russia (魯西亜) / a surname

侵略: aggression; invasion; raid

侵食: erosion, corrosion