Green’s Dictionary of Slang

prim n.

[SE prim, ‘consciously or affectedly strict or precise; formal, stiff, demure’ (OED)]

‘a silly, empty, starcht fellow’ (B.E.).

[UK]Hickscorner Ci: I wolde that hell were full of suche prymmes Than wolde I renne thyder on my pynnes As fast as I myght go.
[UK]J. Rastell Gentleness and Nobility line 926: Trow ye that I care for these nise proude primmys, These paintyd popagays that hold up their chynnys And loke so smoterly.
[UK]B.E. Dict. Canting Crew n.p.: Prim, a silly empty starcht Fellow.