In a manner clear to the eye or mind
distinctly, plainly, visibly, manifestly, unmistakably, perceptibly, in full view, transparently, discernibly, decidedly, starkly, glaringly, incontestably, undoubtedly, indubitably, noticeably, admittedly, before one's eyes, prominently, obviously, patently, openly, overtly, observably, certainly, apparently, recognizably, conspicuously, in plain sight, definitely, markedly, evidently, to all appearances, precisely, lucidly, coherently, articulately, intelligibly, comprehensibly, understandably, simply, unambiguously, explicitly, in plain English, limpidly, pellucidly, translucently, with clarity, in focus, legibly, readably; see also apparently.
Antonyms hazily, vaguely, fuzzily.
In a manner easy to hear
distinctly, sharply, acutely, ringingly, penetratingly, sonorously, audibly, aloud, out loud, articulately, intelligibly, bell-like, with absolute clarity, with good articulation.
Antonyms indistinctly, mutteringly, unclearly.