* Negative connotation: "The upstart company challenged the industry leader, but they lacked the experience and resources to succeed."
* Neutral connotation: "The upstart entrepreneur quickly gained a following with his innovative product."
* Positive connotation: "Despite being an upstart in the field, the young scientist made groundbreaking discoveries."
The connotation of "upstart" can vary depending on the context. It can be used to describe someone who is new, ambitious, and possibly arrogant, or it can be used to describe someone who is innovative and resourceful.