Sailor starts on the more colourful deck? (5)
I believe the answer is:
tarot
'colourful deck?' is the definition.
'tarot' can be an answer for 'deck?' (I've seen this before). I'm not certain of the 'colourful' bit.
'sailor starts on the more' is the wordplay.
'sailor' becomes 'tar' (slang term for a sailor).
'starts' suggests taking the first letters.
'more' means one lot of letters go next to another (some letters added to the previous ones).
The first letters of 'on the' is 'ot'.
'tar'+'ot'='TAROT'
Can you help me to learn more?
(Other definitions for tarot that I've seen before include "Picture card" , "78-card pack" , "Sort of card" , "Fortune teller" , "one may have been taken from deck" .)