goalkeeper (n)
 /ˈɡoʊlˌkiː.pɚ/

the player who stands in the team's goal to try to stop the other team from scoring

defender (n)
/dɪˈfen.dɚ/

someone in a sports team who tries to prevent the other team from scoring points, goals, etc.

centre back (n)
/ˈsent̬ɚ bæk/

a center back is a player who helps form the central part of his team's defense, generally as part of a back three, back four or back five

midfielder (n)
 /ˈmɪdˌfildər/ 

a player who plays in the central area of a sports field, or a central structure of a sports team

attacking midfielder (n)
/əˈtækɪŋ ˌmɪdˈfɪəl.dər/ 

a midfield player who is positioned between central midfield and the team's forwards, and who has a primarily offensive role

winger (n)
/ˈwɪŋ.ɚ/

a player whose position is at either of the two sides of the field in a team game such as football

referee (n)
 /ˌref.əˈriː/

a person who is in charge of a sports game and who makes certain that the rules are followed

commentator (n)
/ˈkɑː.mən.teɪ.t̬ɚ/

a reporter for radio or television who provides a spoken description of and remarks on an eventas it happens

supporter (n)
/səˈpɔːr.t̬ɚ/

someone who wants a particular team to win and might show it by going to watch them play

linesman (n)
/ˈlʌɪnzmən/

an official in some sports who is responsible for deciding when the ball has crossed the line that marks the edge of the playing area

hooligan (n)
/ˈhuː.lɪ.ɡən/

a violent person who fights or causes damage in public places

red card (n)
/red kɑːrd/

a card shown by the referee to a player who has broken the rules of the game and is not allowed to play for the rest of the game

yellow card (n)
/ˈjel.oʊ kɑːrd/

a card is shown to player by the referee as a warning that the player doesn't abide by a rule

coach (n)
/koʊtʃ/

someone whose job is to train and organize a sports team

transfer (n)
/ˈtræns.fɜːr/

a player who has moved from one sports team to another

reserve team (n)
/rɪˈzɜr:v tiːm/

a team consisting of players who are not in the first team, but who play in a league against reserve teams from other clubs

caution (n)
/ˈkɑː.ʃən/

a punishment for breaking the rules in a football game in which the referee writes the player's name in a book and holds up a yellow card

stimulant (n)
/ˈstɪm.jʊ.lənt/

a substance, such as a drug, which makes the mind or body more active

strategy (n)
/ˈstræt̬.ə.dʒi/

a detailed plan for achieving success in situations such as war, politics,business, industry, or sport

striker (n)
/ˈstraɪ.kɚ/

a football player whose main job or skill is scoring goals