Where does this definition of be doubtful of come from?
This entry for be doubtful of is sourced from GetWord Corpus, one of the dictionaries and corpora merged into Lughet.
Is be doubtful of a noun, verb, or something else?
In this entry, be doubtful of is tagged as 2v..
What is Lughet?
Lughet is a free trilingual dictionary covering nearly five million entries across Uyghur, Chinese, and English, drawn from more than ten source dictionaries and corpora.