Antonyms of adj laid-back

1 sense of laid-back

Sense 1
laid-back, mellow -- (unhurried and relaxed; "a mellow conversation")

INDIRECT (VIA relaxed) -> tense -- (in or of a state of physical or nervous tension)

Similarity of adj laid-back

1 sense of laid-back

Sense 1
laid-back, mellow -- (unhurried and relaxed; "a mellow conversation")
       => relaxed (vs. tense) -- (without strain or anxiety; "gave the impression of being quite relaxed"; "a relaxed and informal discussion")