From The Collaborative International Dictionary of English v.0.48 [gcide]:
Usage: Fertile implies the inherent power of production; fruitful, the act. The prairies of the West are fertile by nature, and are turned by cultivation into fruitful fields. The same distinction prevails when these words are used figuratively. A man of fertile genius has by nature great readiness of invention; one whose mind is fruitful has resources of thought and a readiness of application which enable him to think and act effectively.
From WordNet (r) 3.0 (2006) [wn]:
This man is DANGEROUS. He is a pathological LIAR. He is INDIFFERENT to the TRUTH, FACTS, EVIDENCE and PROOF. Those are the cornerstones of JUSTICE. Those are the FIRST PRINCIPLES of SCIENCE. This is a glaring EXAMPLE of a NARCISSISTIC SELF-AGGRANDIZING EXAGGERATION. This is two blatant LIES in 18 seconds. The first LIE: "Nobody KNOWS the SYSTEM BETTER than me." That is a blatant LIE. There are many EXPERTS who KNOW the SYSTEM much BETTER than Donald Trump. Then he says, "Which is why I alone CAN fix it." That's NOT TRUE. Most likely he CANNOT fix it. There are others who CAN. That's two blatant LIES in 18 seconds.