Green’s Dictionary of Slang

Welsh adj.

In compounds

Welsh cricket (n.) [negative stereotyping]

a louse.

[UK]Greene Quip for Upstart Courtier F: Before he [the taylor] had no other cognizance but a plaine Spanish needle with a Welsh cricket at top.
Welsh parsley (n.)

hemp, as used in the hangman’s rope.

[UK]Fletcher Elder Brother I ii: In tough Welsh-parsly, which our vulgar Tongue Is strong hempen halters.
[UK]T. Randolph Hey for Honesty IV i: This is a rascal deserves to ride up Holborn, And take a pilgrimage to the triple tree, To dance in hemp Derrick’s coranto: Let’s choke him with Welsh parsley.