Literary and fairly bookish - closer to English 'chip off the old block', but more formal. 肖 here means 'to resemble', not 'Xiao' the surname, so it is read xiào (4th tone) - NOT xiāo.
mistakes
Do not confuse with 孝子 'filial son'. Both are pronounced xiàozǐ, but 肖子 is about resemblance while 孝子 is about filial piety.
