English Proficiency Programme
Vocabulary Building
Lots of words can be learnt together through
           
Etymological Connections (word-root, prefixes, suffixes etc)
    and
           
Semantic Connections (meaning, synonyms, nuances, usage etc).
In the course of your normal reading, suppose
you encountered the word     "corroborate"    
a few times here and there.
Interesting word!
As you look up dictionaries, thesauruses and other resources (in traditional bound books as well as web-sites), you find a lot of illuminating material.
Corroborate (v).
Root: Latin 'roborare', to strengthen, from 'robur', for strength.
Meaning: to confirm.
Etymological connections: corroborable (adj), corroborant (adj), corroborative (adj), corroboration (n), corroborator (n) ... and distantly, ... robust (adj).
Synonyms: confirm, strengthen, verify, justify, authenticate, substantiate, endorse, validate etc.
Usage: in sentences.
Special Sense: Information "B" corroborates
information "A".
It means that "B" supports "A"
  and   "A" supports "B".
Some rich web-sites.
Important: You should have something
like 'normal reading' to encounter interesting words,
AND then
take interest to get into such scrutiny - once in a while.
Read a lot.   Yes, fiction.