Sir

お兄さん

oniisan

(address to any male, especially if his name or proper address is unknown)

サー

sā

(title)

僕

boku

(address to any male, especially if his name or proper address is unknown)

卿

kyō

(title)

旦那

danna

(man of a higher rank or position)

旦那

danna

(address to any male, especially if his name or proper address is unknown)

旦那様

danna-sama

(address to any male, especially if his name or proper address is unknown)