直ちょく進しん性せいMeaningsNoun1. straight-line stability (of a vehicle); directional stability2. straight-line propagation (e.g. of light or sound); straightnessKanji used直straight進advance性nature (of a person)Composed of直ちょく進しんgoing straight on; going straight aheadNoun性せいnature (of a person); sex; gender; sex (i.e. sexual attraction, activity, etc.); -ty; -ity; -ness; -cyNoun