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