Sycophant joining queen in plant (7)
I believe the answer is:
creeper
'in plant' is the definition.
'creeper' can be an answer for 'plant' (I've seen this before). I'm not certain of the 'in' bit.
'sycophant joining queen' is the wordplay.
'sycophant' becomes 'creep' (I've seen this before).
'joining' is a charade indicator (letters next to each other).
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'creep'+'er'='CREEPER'
Can you help me to learn more?
(Other definitions for creeper that I've seen before include "Climber" , "Ivy is one" , "Climbing-plant" , "one going up the wall after 8 [STATE = VIRGINIA]" , "Variety of plant" .)