tim-tim, n. — Green’s Dictionary of Slang

tim-tim n.

[Carib.E. excl. tim-tim! used by a story-teller to indicate that he/she is about to tell a folk-tale. ? ult. Fr. tiens, hello! look! or SE (it’s) time]

(W.I.) an unreliable story, a fantasy; also as adj.

1965		Dominica Herald 15 May 1: Eyewitness statements [...] cannot at this time be confirmed, nor can some of the many tim-tims going on around town, including tales of purposeful destruction.
1966		J. Rhys Wide Sargasso Sea 71: So you believe in that tim-tim story about obeah, you hear when you so high?