The term 'affirm under oath' refers to a legal process in which an individual makes a statement or promise that is legally binding. The crossword solutions for this term are 'ATTEST' (6 letters), 'PERJURE' (8 letters), 'ATTESTED' (8 letters), 'SWEAR' (5 letters) and 'swearto' (7 letters). ATTEST means to certify or confirm, while PERJURE means to make a false statement under oath. ATTESTED means to have been certified or confirmed, while SWEAR means to make a solemn promise or statement. Swearto means to make a solemn promise or statement under oath. All of these words refer to the same process of making a legally binding statement or promise.