The Hebrew in Psalm 55:13 that is translated as «familiar friend» or similar in English is translated in the Contemporary Chichewa translation (2002/2016) with bwenzi langa la pondaapanʼpondepo, lit. «a friend of step-here-I-also-step-there,» i.e. someone with whom one is a deep friendship with. (Source: Mawu a Mulungu mu Chichewa Chalero Back Translation)
See also close friend.