Thanks to lakes being huge (4)
I believe the answer is:
tall
'being huge' is the definition.
(thesaurus)
'thanks to lakes' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'to lakes' becomes 'LL' (L is an abbreviation for lake).
'ta'+'ll'='TALL'
(Other definitions for tall that I've seen before include "Of great stature" , "Remarkable" , "Above average height" , "Lofty; unlikely" , "Towering" .)