The phrase 'a marked weakness' is correct and usable in written English.
This phrase is used to describe something that stands out and is particularly noticeable or pronounced. For example, "Her inability to plan ahead was a marked weakness."
He regained movement, but his right side has a marked weakness and his nervous system was damaged.
Given that Cain is set to be addressing foreign policy issues at his speech in Michigan, his aides will no doubt be hoping for a smoother performance in an area that has previously been a marked weakness for the controversial candidate.
There was a marked weakness to his right side, he couldn't turn his head and had difficulty walking.
As far as he was concerned, business people exhibit a marked weakness for rigging the system in their favor.
Despite the weakness of the lead story, the second issue was a marked improvement over the first, with well-received stories by Nelson S. Bond and John Russell Fearn (as "Thornton Ayre").
"Both the manufacturing (especially) and construction (to a limited extent) surveys have shown activity picking up in August after marked weakness in July, and we suspect that this will be the case for the services sector as well," he said.
This is usually attributed to foot and ankle joint restrictions [ 3, 8] and marked weakness of intrinsic foot muscles [ 19].
Patients with more-severe hypercalcemia may have nausea, vomiting, weight loss, constipation, bone pain, and more-marked weakness and depression.
Results showed that both simulated muscle weakness conditions had a marked effect on the lifting strategy.
It is a marked change from a year ago.
With the weakness of the pound, the credit market freeze and the subsequent recession, "we noticed a marked downturn in interest from new buyers and inquiries from late 2008 to mid-2009," Mr. Brown said.
