Irrepressible, I get right in among the others (9)
'irrepressible' is the definition.
(I've seen this before)
'i get right in among the others' is the wordplay.
'get' says to put letters next to each other.
'right' becomes 'lien' (I've seen this before).
'in among' means one lot of letters goes inside another.
'the others' becomes 'rest' (I've seen this in other clues).
'ilien' going into 'rest' is 'RESILIENT'.
(Other definitions for resilient that I've seen before include "Elastic", "able to withstand disappointment", "Bouncy", "Able to recover quickly", "recovering easily from shock".)