probablyとは

発音

• (Received 発音) IPA^(key): /ˈpɹɒbəbli/
• (Received 発音, 口語) IPA^(key): /ˈpɹɒbli/
• (General American) IPA^(key): /ˈpɹɑbəbli/
• (General American, 口語) IPA^(key): /ˈpɹɑbli/

副詞

probably (comparative more probably, superlative most probably)

1. In all likelihood.
   • 1922, Ben Travers, chapter 1, in A Cuckoo in the Nest‎^[1]:

     “[…] the awfully hearty sort of Christmas cards that people do send to other people that they don't know at all well. You know. The kind that have mottoes […] . And then, when you see [the senders], you probably find that they are the most melancholy old folk with malignant diseases. […]”

   • 2013 May-June, William E. Conner, “An Acoustic Arms Race”, in American Scientist, volume 101, number 3, page 206-7:

     Earless ghost swift moths become “invisible” to echolocating bats by forming mating clusters close […] above vegetation and effectively blending into the clutter of echoes that the bat receives from the leaves and stems around them. Many insects probably use this strategy, which is a close analogy to crypsis in the visible world—camouflage and other methods for blending into one’s visual background.

同意語

• (in all likelihood): likely, perhaps, maybe, possibly, presumably, most likely, doubtless, in all probability, perchance, as likely as not, as like as not