NASTAIIN- Lexicography
A Wa Na or A'aana : The root word meaning: To aid ,assist, help, succour
I'aana-t: Deliver, free. (F.Steingass and Abdul Hafeez Baizawi).

COMPARISON WITH SYNONYMS AND CONTRADISTINCTION:
A Wa Na or A'aana : To help in all manners, way . (It is common ).

"Nasara": To help to remove distress
"Ayyada": To help to strengthen
"Azzara": To help out of respect
"Azzaza": To help so that the weakness is removed
"Zaahara": To back
"Rafada": Finally continue to support a needy
"Rawaa'a": To put a permanent support, backing
"Amadda": To supply (provide supplies)
"Nasir wa Nasiir": Helper at the time of excess and injustice
"Havaari": Special party of helpers
"Walii wa Maulaa": Near friend, seconder and helper.
"Shahiid": To be a witness in support on the occasion
"Zahiir": Helper on whom one can fall back upon
"Waziir": Helper in excess or burden of work
"Udzud": Helping hand (helper)
(Mutaraadifaatul Quran, Abdur-Rahmaan Kailani)

From above it is clear that in this verse a very general and all-encompassing word Nastaiin" from A Wa Na or A'aana " has been used.

For different shades of meaning, usage and derivatives of the root word, see pages 691, Al-Muajamul Mufaharas, Muhammad Fawad Abdul Baqi.