Striving snake I telephone (8)
I believe the answer is:
aspiring
'striving' is the definition.
(I've seen this before)
'snake i telephone' is the wordplay.
'snake' becomes 'asp' (asp is a kind of snake).
'telephone' becomes 'ring' (synonyms).
'asp'+'i'+'ring'='ASPIRING'
(Other definitions for aspiring that I've seen before include "Strongly desiring to achieve" , "Ambitious, hopeful" , "Wanting to get high" , "Having a strong desire to achieve something" , "Striving" .)