This post explains how the adjective ‘clear cut’.
When a penalty is awarded, fans and pundits talk about the decision. Was it a good decision? Was it a harsh decision? Was it a mistake by the referee? If everyone agrees that it was a penalty, you can use clear cut in a phrase, as in ‘It was a clear-cut penalty‘. This means there was no doubt, everyone can see that the decision was correct; there is no argument. When a penalty decision is not clear cut, you might use the phrase ‘It was a harsh penalty.’
Example: Cambridge United boss Jez George tells BBC Radio Cambridgeshire he believes his side should have won a “clear-cut” penalty in the second half against Wrexham. (BBC)