plural of party of the first part

(idiomatic) To act self-righteously in accusing another person, believing oneself to be blameless.

plural of firststringer

(idiomatic) Upon first impression or consideration; seemingly, apparently, ostensibly.

(US) In the United States Army, a non-commissioned officer ranking above sergeant first class and below sergeant major; equal in rank to a master sergeant but with greater command authority.

plural of first sergeant

(US) An enlisted rank in the United States Army, of rank E-3, ranking above a private and below a corporal or specialist.

(US, Army) A non-commissioned officer in the United States Army, ranking above a staff sergeant and below a master sergeant or first sergeant.

(modal) After only a superficial examination or review

Familiar with someone, such that one can address them by their first name. / (by extension, humorous) In regular contact with a person or organisation.