in‧for‧mant /ɪnˈfɔːmənt $ -ɔːr-/ noun [countable]
[Word Family: noun: informant, information, informer, misinformation, disinformation; verb: inform, misinform; adjective: informative ≠ UNINFORMATIVE, informed ≠ uninformed; adverb: informatively]

1. someone who secretly gives the police, the army etc information about someone else Synonym : informer:
One of the witnesses was a paid informant for the FBI.

2. technical someone who gives information about their language, social customs etc to someone who is studying them

[TahlilGaran] Dictionary of Contemporary English ▲