for lack of trying

• for want of trying

for lack of trying

1. (chiefly in the negative) Due to a failure to make a significant enough effort.

   The solution has not yet been found, and it has not been for lack of trying.

• “not for lack of trying”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “it is not for lack/want of trying”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “it is not for lack/want of trying” (US) / “it is not for lack/want of trying” (UK) in Macmillan English Dictionary.
• “for want of trying/for lack of trying”, in Collins English Dictionary.