Reportedly observe explosive device, something found on beach (8)
I believe the answer is:
seashell
'device something found on beach' is the definition.
I can't judge whether this definition defines the answer.
'reportedly observe explosive' is the wordplay.
'reportedly' shows a homophone (sound like).
'observe' becomes 'see' (I've seen this before).
'explosive' becomes 'shell' (I can't justify this - if you can you should believe this answer much more).
'see' is a homophone of 'sea'.
'sea'+'shell'='SEASHELL'
Can you help me to learn more?
(Other definitions for seashell that I've seen before include "home by the coast, perhaps" , "scallop?" , "periwinkle?" , "Case of mollusc" , "hermits abode" .)