Tiny chap featured in work is source of memorably cheery outlook (8)
I believe the answer is:
optimism
'cheery outlook' is the definition.
'optimism' can be an answer for 'outlook' (I have seen 'Confident outlook ' mean 'optimism' so perhaps 'outlook' could also mean 'optimism'). I'm unsure of the 'cheery' bit.
'tiny chap featured in work is source of memorably' is the wordplay.
'tiny chap' becomes 'tim' (I've seen this before).
'featured in' is an insertion indicator.
'work' becomes 'op' (abbreviation for opus).
'source of' suggests taking the first letters (the start - or source - of the word).
The initial letter of 'memorably' is 'm'.
'op'+'is'='opis'
'tim' going within 'opis' is 'optimis'.
'optimis'+'m'='OPTIMISM'
Can you help me to learn more?
(Other definitions for optimism that I've seen before include "Feeling that all is going to turn out well" , "Hopeful nature" , "Looking on the bright side" , "Confidence in the future" , "Mind-frame that looks on the bright side" .)