perspiration UK /ˌpɜːspəˈɹeɪʃən/US /ˌpɝspəˈɹeɪʃən/ noun3 •The action or process of perspiring. •Sweat (fluid).Passing his hand across his forehead he withdrew it, wet with drops of perspiration. — 1897 •Synonym of hard work.Genius is 1 per cent. inspiration and 99 per cent. perspiration. — 1910 formsperspirations