problematic

The president had accused Intel CEO Lip-Bu Tan of having problematic ties with China and called on him to resign, though Mr Tan called the accusations "misinformation".

In each case, a leader he sees as a natural, if problematic ally – Russian President Vladimir Putin and Israeli Prime Minister Benjamin Netanyahu – has thrown a massive spanner in the wheels of White House peace-making.

Still, his refusal to admit error, or to abandon his problematic colleague, came to symbolize for many the arrogance of the new mandarins of the biological sciences.

There are, unquestionably, more problematic targets for the world to set its sights on.

In this case the UK's high inflation, and any doubt after the summer U-turns about the government's control over events, could quickly turn problematic.