The word "sportief" is used in three common translations. The link with the noun "sport" is obvious.

1. sporty, sports [adverb/adjective]

Here "sportief" is used to describe appearance or character.

Examples:
– "Ik heb afgelopen zaterdag een proefrit gemaakt in een Toyota Prius, maar ik denk dat ik toch voor een sportievere auto ga." 
("I test-drove the Toyota Prius last Saturday, but I think that I prefer / will go for a more sporty car.")

– "Leuk jasje heb je aan, sportief hoor!" 
("Nice jacket! Sporty/casual!")

Related word:
– Sport: sport [noun] [de sport, de sporten]. Also used in the translation of "sports" (the category).

2. sports-loving, fond of sports [adverb/adjective]

Here you can use "sportief" to say that somebody likes to sport or exercise, or that the person is in fact quite fit.

Examples:
– "Madelon gaat een paar keer per week fitnessen. Ze is best wel sportief!" 
("Madelon goes to fitness training a few times a week. She likes to exercise / she is quite fit!")

3. sportsmanlike, sporting [adverb/adjective]

The expression "sportief zijn" is commonly used in the context of
this translation. It translates as "to be a good sport (about
something)". Along the same lines you can also say "dat is (niet) sportief (van jou)" (something like "that’s (not) sportsmanlike (of you)").

Examples:
– "Marc is heel sportief, want hij geeft doorgaans direct zijn fouten toe." 
("Marc is a good sport, because he usually admits his mistakes straight away.")

– "Het gedrag van de supporters was niet bepaald sportief te noemen…" 
("The behaviour of the supporters wasn’t quite sportsmanlike…" Lit. : "… couldn’t really be called sporting".)

– "Ik zal dit keer de rekening betalen." – "Tof, dat is sportief van je." 
("I will pick up / pay the bill this time." – "Cool. You are being a good sport.")

Expression:
– "Iets sportief opvatten": to take something well/with grace.

Related word:
– Eerlijk: fair [adjective/adverb].