ご苦労様[gokurousama] thank you very much for your ...
御苦労さん[gokurousan] I appreciate your efforts
慰労[irou] recognition of services
過労[karou] overwork
過労死[karoushi] death from overwork and mental stress

気苦労[kigurou] worry
漁労[gyorou] fishing
共労者[kyourousha] coworker
勤労[kinrou] labor
勤労階級[kinroukaikyuu] salaried class

医博[ihaku] doctor of medicine
該博[gaihaku] profundity
該博な知識[gaihakunachishiki] profound knowledge
商学博士[shougakuhakushi] Doctor of Commercial Science
大英博物館[daieihakubutsukan] British Museum

賭博[tobaku] gambling
博愛[hakuai] charity
博愛家[hakuaika] philanthropist
博愛主義[hakuaishugi] philanthropism
博引傍証[hakuinboushou] citing copious references