Word of Qualification is a term used to describe a phrase or statement that is used to modify or limit the meaning of another phrase or statement. The two words used in this crossword are 'BUT' and 'UNLESS'. 'BUT' is a conjunction used to introduce a phrase that contrasts with the preceding phrase, while 'UNLESS' is a conjunction used to introduce a phrase that expresses a condition on which the preceding phrase depends. Together, these two words can be used to modify or limit the meaning of a phrase or statement.