From Longman Dictionary of Contemporary Englishthimblefulthim‧ble‧ful /ˈθɪmbəlfʊl/ noun [countable + of] informalLITTLE/NOT MUCH a very small quantity of liquid
Examples from the Corpus
thimbleful• Early attacks of stage fright were cured by a thimbleful of Courvoisier.• I don't know what the great lady is on but I'd sell my Equity Card for a thimbleful.• A lot of tax money had gone for a thimbleful of water.• A thimbleful of water, sir? he asked the ant.• Scented by infusion with wild tarragon, like no other sorbet I have ever tasted, a mere thimbleful did the trick. 