Sports watch:

most often steel, can be gold or titanium, mix of brushed and polished surfaces frequent, mix of materials possible
usually on a metal bracelet, often with not more than 3 rows (Oyster style)
up to 42mm diameter though with the big watch craze some might allow more. only allow more for seriously large wrists.
up to 14mm thick, must be proportionate to diameter
most often automatic with notable exception of ETA6497 bases
usually has central seconds and date
can have more lume and also lume on seconds hand
may have numbers for minutes
may have fancier hands e.g. sword a la Blancpain
all kinds of indices possible
dial can be dark or even colored though nothing crazy, mostly blue
often has a screwdown crown and caseback
WR at least 100m
No helium valves, chronos or diving bezels. A discrete GMT, alarm or power reserve is permissible.
Worn for anything except ballroom but mostly leisure oriented. The more elegant examples can be worn with a suit.