Joiner outside university left little flower (7)
I believe the answer is:
rivulet
'little flower' is the definition.
'rivulet' can be an answer for 'flower' (thesaurus). I am unsure of the 'little' bit.
'joiner outside university left' is the wordplay.
'joiner' becomes 'rivet' (I am not sure about this - if you are sure you should believe this answer much more).
'outside' indicates putting letters inside (some letters go outside others).
'university' becomes 'U' (abbreviation for university).
'left' becomes 'l' (common abbreviation).
'u'+'l'='ul'
'rivet' going around 'ul' is 'RIVULET'.
Can you help me to learn more?
(Other definitions for rivulet that I've seen before include "Brook" , "Big stream" , "fast stream" , "burn" , "Vile rut for small stream" .)