Matches documents that have fields matching a wildcard expression. Supported wildcards are *, which matches any character sequence (including the empty one), and ?, which matches any single character. Note this query can be slow, as it needs to iterate over many terms. In order to prevent extremely slow wildcard queries, a wildcard term should not start with one of the wildcards * or ?. The wildcard query maps to Lucene WildcardQuery.
{
"wildcard" : { "user" : "ki*y" }
}
A boost can also be associated with the query:
{
"wildcard" : { "user" : { "value" : "ki*y", "boost" : 2.0 } }
}
Or :
{
"wildcard" : { "user" : { "wildcard" : "ki*y", "boost" : 2.0 } }
}