Cases of word usage

1) to get or gain (something) by work, skill or ability, by one's own efforts or behaviour (acquire)

2) quick at seeing how to gain an advantage (astute)

3) a political leader who tries to gain support by speeches appealing to the feedings instead of to reason (demagogue)

4) the two on playing-cards or dice; (tennis) the score of 40 each after which either side must gain two successive points to win the set (deuce)

5) a test or trial carried out carefully in order to study what happens and gain new knowledge (experiment)

6) to make oneself likes, especially in order to gain an advantage (ingratiate)

7) to gain knowledge of, become skilled in, (a subject being studied, a particular activity) (learn)

8) remaining when nothing more is to be taken away; a kind of material with loose threads of cotton, wire etc; an object made using this; to gain (an amount) as a profit (net)

9) a person who is (more) anxious to gain an advantage for herself or himself (than to consider whether it is fair) (opportunist)

10) something said or done to gain an advantage over a person (ploy)