Hi Puys...
I am not sure whether it is effective way to improve the vocab... but try following questions...
Select the word from options with opposite meaning
Q1] SOIGEN
- rustic
- caring
- conservative
- fertile
Q2] RECREANT
- prodigal
- extant
- sterile
- valiant
Q3] DISTAFF
- ambiguous
- genuine
- intelligent
- masculine
Q4] ADVENTITIOUS
- cautious
- integral
- passive
- sporty
Q5] GRIMACE
- stiff
- cut-open
- scold
- smile
All the best.....