adverb
just a little; the smallest amount; not at all (with negative)
Archaic adverb meaning 'even a tiny bit' or 'the slightest amount'. Often used in negative constructions to mean 'not at all'. Found in classical literature and poetry; not used in modern everyday speech.
露ばかりも疑わずに彼を信じた。
I trusted him without the slightest doubt.
その言葉には露ばかりの真実
There is not a grain of truth in those words.
Modern equivalent meaning 'not at all' or 'not the least bit', used in negative sentences. 露ばかり is its archaic counterpart.
The noun 露 means 'dew' and is the source of the adverbial sense 'a tiny amount', by metaphorical extension. 露ばかり literally means 'even as much as a dewdrop'.
From 露 (つゆ, 'dew') + ばかり ('approximately, only'), literally 'even as much as a dewdrop'. The metaphorical extension to 'a tiny amount' is natural, but the exact historical development is uncertain.