Antonyms of adj lax

4 senses of lax

Sense 1
lax, slack -- (lacking in rigor or strictness; "such lax and slipshod ways are no longer acceptable"; "lax in attending classes"; "slack in maintaining discipline")

INDIRECT (VIA negligent) -> diligent -- (characterized by care and perseverance in carrying out tasks; "a diligent detective investigates all clues"; "a diligent search of the files")

Sense 2
lax (vs. tense) -- (pronounced with muscles of the tongue and jaw relatively relaxed (e.g., the vowel sound in `bet'))

tense (vs. lax) -- (pronounced with relatively tense tongue muscles (e.g., the vowel sound in `beat'))
        => constricted -- (especially tense; especially in some dialects)

Sense 3
lax (vs. tense) -- (lacking in strength or firmness or resilience; "a lax rope"; "a limp handshake")

tense (vs. lax) -- (taut or rigid; stretched tight; "tense piano strings")
        => overstrung -- (too tightly strung; "an overstrung archery bow")
        => taut, tight -- (pulled or drawn tight; "taut sails"; "a tight drumhead"; "a tight rope")

Sense 4
lax, loose -- (emptying easily or excessively; "loose bowels")

INDIRECT (VIA unconstipated) -> constipated -- (have difficult or incomplete or infrequent evacuation of the bowels)

Similarity of adj lax

4 senses of lax

Sense 1
lax, slack -- (lacking in rigor or strictness; "such lax and slipshod ways are no longer acceptable"; "lax in attending classes"; "slack in maintaining discipline")
       => negligent (vs. diligent) -- (characterized by neglect and undue lack of concern; "negligent parents"; "negligent of detail"; "negligent in his correspondence")

Sense 2
lax (vs. tense) -- (pronounced with muscles of the tongue and jaw relatively relaxed (e.g., the vowel sound in `bet'))

Sense 3
lax (vs. tense) -- (lacking in strength or firmness or resilience; "a lax rope"; "a limp handshake")
       => drooping, droopy, sagging -- (hanging down (as from exhaustion or weakness))
       => limp -- (lacking in strength or firmness or resilience; "gave a limp handshake"; "a limp gesture as if waving away all desire to know" G.K.Chesterton; "a slack grip")
       => floppy -- (hanging limply; "a spaniel with floppy ears")
       => loose, slack -- (not tense or taut; "the old man's skin hung loose and grey"; "slack and wrinkled skin"; "slack sails"; "a slack rope")
       => loose-jointed -- (loosely articulated or constructed; "a loose-jointed paragraph")
       => tensionless -- (free from tension)
          Also See-> loose#3

Sense 4
lax, loose -- (emptying easily or excessively; "loose bowels")
       => unconstipated (vs. constipated), regular -- (not constipated)