Definition of peeny-wally in US English:

peeny-wally

noun

Jamaican, Caribbean
  • A firefly; specifically a luminescent click beetle (family Elateridae), especially of the largest Jamaican species, Pyrophorus plagiophthalmus.

Origin

1960s. Origin uncertain; perhaps humorous blend of Carribean English peeny very small, tiny, and peely-wally.

Pronunciation

peeny-wally

/ˈpiːnɪˌwɒli/