To dream of a competition represents feelings about being challenged. Struggling to remain become dominant in a situation. Your attempt to avoid jealousy or embarrassment. Struggling against other people in your life with similar goals. Situations in life where you are unwilling to accept defeat or a passive role.
Negatively, competition in a dream my reflect issues with being overly-dominant or controlling. Anxiety about being viewed as a loser. Fearing that a passive role in a situation will result in total humiliation. An ego that is out of control. A need to maximize. A need to feel better than others. Fear of losing an opportunity.
Example: A woman dreamed of being in a very dangerous life threatening competition. In waking life she was struggling for social dominance against her mother-in-law who simply would not accept her in a leading role.
Example 2: A woman dreamed of watching a swimming . In waking life she was interested in a man and began to realize that other women were interested in him too.