Formalist(n.) One overattentive to forms, or too much confined to them; esp., one who rests in external religious forms, or observes strictly the outward forms of worship, without possessing the life and spirit of religion.
Thesaurus Entries
Babbitt, High-Churchist, Holy Willie, Joseph Surface, Mawworm, Middle American, Pecksniff, Pharisee, Philistine, Sabbatarian, Tartuffe, Vicar of Bray, affecter, anal character, bluestocking, bourgeois, burgher, canter, canting hypocrite, chameleon, compulsive character, conformer, conformist, conventionalist, dissembler, dissimulator, formularist, formulist, hypocrite, lip server, lip worshiper, liturgist, methodologist, middle-class type, model child, organization man, parrot, pedant, perfectionist, pharisee, pietist, pious fraud, plastic person, poser, precieuse, precieux, precisian, precisianist, precisionist, purist, ranter, religionist, religious hypocrite, ritualist, sacramentarian, sheep, sniveler, snuffler, spiritual humbug, square, teenybopper, temporizer, timepleaser, timeserver, trimmer, weathercock, whited sepulcher, yes-man