Happily, her malt is what can give winger a lift (7)
I believe the answer is:
thermal
'a lift' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'happily her malt is what can give winger' is the wordplay.
'her malt' can be anagrammed to 'THERMAL'.
Though, I am not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for thermal that I've seen before include "Her malt became heat-related" , "Relating to heat" , "Type of air current" , "Warm or hot, say air or spring" , "Rising current (used by gliders)" .)