Spike and Sam somehow say the wrong thing (8)
I believe the answer is:
misspeak
'spike and sam somehow say the wrong thing' is the definition.
I can't judge whether this definition defines the answer.
'spike and sam somehow' is the wordplay.
'and' is a charade indicator (letters next to each other).
'somehow' indicates anagramming the letters.
'spike' put after 'sam' is 'samspike'.
'samspike' is an anagram of 'MISSPEAK'.
Can you help me to learn more?
(Other definitions for misspeak that I've seen before include "say, the wrong way" , "Express oneself badly" , "say, wrongly" , "Emulate Mrs Clinton" .)