chivalrous spirit; chivalrous man; knight in shining armor
Refers to a man who acts with chivalry, defending the weak and upholding justice, often in a somewhat old-fashioned or romanticized way. Can also denote the spirit itself.
ruffian pretending to be chivalrous
A less common, somewhat dated usage for a rough person who puts on a show of chivalry, often with an underlying selfish or violent nature.
He can't ignore people in trouble; he's a true knight in shining armor.
Acting the chivalrous man, he helped her.
That man pretends to be chivalrous, but he's really just a ruffian.
騎士道 is the Western concept of knighthood and chivalry, whereas 男伊達 is a native Japanese term for a chivalrous man or spirit, often with a more down-to-earth, sometimes theatrical nuance.
Standard kanji spelling.
Rarely used kanji form; may be confused with 男達 (おとこたち).
Compound of 男 (man) and 伊達 (dandyism, showiness). Originally referred to a man who dresses stylishly and acts with bravado, later acquiring the meaning of a chivalrous man who defends the weak. The exact historical derivation is uncertain.