Many grabbing uniform: one forgot taking it (5)
I believe the answer is:
lotus
'one forgot taking it' is the definition.
(plant causing forgetfulness in Greek mythology)
'many grabbing uniform' is the wordplay.
'many' becomes 'lots' (I've seen this before).
'grabbing' indicates putting letters inside.
'uniform' becomes 'u' (phonetic alphabet: alpha, bravo, charlie etc.).
'lots' enclosing 'u' is 'LOTUS'.
(Other definitions for lotus that I've seen before include "Aquatic plant" , "Indian waterlily" , "Water lily - fruit inducing forgetfulness" , "Large water lily" , "Mythical fruit inducing state of luxurious dreaminess" .)