Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb pen-up

1 sense of pen up

Sense 1
pen up, fold -- (confine in a fold, like sheep)
       => restrain, confine, hold -- (to close within bounds, limit or hold back from movement; "This holds the local until the express passengers change trains"; "About a dozen animals were held inside the stockade"; "The illegal immigrants were held at a detention center"; "The terrorists held the journalists for ransom")

Antonyms of adj pent-up

1 sense of pent-up

Sense 1
pent-up, repressed -- (characterized by or showing the suppression of impulses or emotions; "her severe upbringing had left her inhibited"; "a very inhibited young man, anxious and ill at ease"; "their reactions were partly the product of pent-up emotions"; "repressed rage turned his face scarlet")

INDIRECT (VIA inhibited) -> uninhibited -- (not inhibited or restrained; "uninhibited exuberance")

Similarity of adj pent-up

1 sense of pent-up

Sense 1
pent-up, repressed -- (characterized by or showing the suppression of impulses or emotions; "her severe upbringing had left her inhibited"; "a very inhibited young man, anxious and ill at ease"; "their reactions were partly the product of pent-up emotions"; "repressed rage turned his face scarlet")
       => inhibited (vs. uninhibited) -- (held back or restrained or prevented; "in certain conditions previously inhibited conditioned reactions can reappear")