Give meaning of former grassland (7)
I believe the answer is:
explain
'give meaning' is the definition.
Although both the answer and 'meaning' are verbs, they are not in the same form of the verb.
'former grassland' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'grassland' becomes 'plain' (I have seen 'Open grassland' mean 'plain' so perhaps 'grassland' could also mean 'plain').
'ex'+'plain'='EXPLAIN'
'of' is the link.
Can you help me to learn more?
(Other definitions for explain that I've seen before include "offer clarification" , "Make understandable" , "Tell us how" , "Make comprehensible" , "Expound" .)