blatant / flagrant
Obvious and unashamed versus conspicuously offensive.
Blatant means obvious and unashamed, often loud in spirit: a blatant lie. Flagrant means conspicuously bad or offensive: a flagrant foul, flagrant abuse. A lie can be both. Use blatant for what is done in the open without shame. Use flagrant for what offends by how bad it is.
Examples
Use It was a blatant attempt to stall.
Use That was a flagrant breach of the rule.
Avoid a flagrant attempt to stall (If you only mean it was obvious, not that it was a grave offense.)