With most of cast Chandler oddly falls (7)
I believe the answer is:
cascade
'falls' is the definition.
(synonyms)
'with most of cast chandler oddly' is the wordplay.
'with' says to put letters next to each other.
'most of' means to remove the last letter.
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
The alternating letters of 'chandler' are 'cade'.
'cast' with its last letter removed is 'cas'.
'cas' put next to 'cade' is 'CASCADE'.
(Other definitions for cascade that I've seen before include "Rush" , "Small waterfall or series of them" , "falls in the river" , "Shower" , "Tumble down (like water)" .)