Applying filters in ElasticSearch

I have an index :idxquesanswer, in which i have a body field:

"body" : {
"type" : "text",
"analyzer" : "synonym_analyzer"
}

synonym_analyzer is:

"filter" : {
            "synonym_filter" : {
              "type" : "synonym",
              "synonyms_path" : "wn_s.txt",
              "updateable" : "true"
            }
          },
          "analyzer" : {
            "synonym_analyzer" : {
              "filter" : [
                "lowercase",
                "synonym_filter"
              ],
              "tokenizer" : "standard"
            }
          }

Here wn_s.txt is the sense dictionary of wordnet.
Now when I search in the body field for some text, it gives incorrect documents as result in output. (I have 300 documents in my index and it's giving all in result)

Why is this happening?