bat noun 1: (to have) bats in the belfry (to be) crazy or eccentric. (c. 1901 —) . Blackwood's Magazine The sahib had bats in his belfry, and must be humoured (1928). Cf. batsadjective, battyadjective. 2: (to go) like a bat out of hell (to go) very quickly. (1921 —) . I.Fleming The motor cyclist...had gone like a bat out of hell towards Baker Street (1961).
bat noun
A rate of stroke or speed, pace. (1824 —) . J.Welcome We turned on to the main...road and started going a hell of a bat across the Cotswolds (1961).
[From the earlier sense, a blow or stroke with a bat, club, etc.]
bat Also batt noun, orig US
A spree or binge. (1848 —) . E.Waugh Why don't you switch to rum? It's much better for you...When did you start on this bat? (1942).