different between expressionless vs thoughtless

English

expression +? -less

expressionless (comparative more expressionless, superlative most expressionless)

thought +? -less

(UK) IPA^(key): /????tl?s/, /????tl?s/
(General American) enPR: thôt’l?s, thôt’l?s, IPA^(key): /???tl?s/, /???tl?s/
(cot–caught merger) enPR: thät’l?s, thät’l?s, IPA^(key): /???tl?s/, /???tl?s/

thoughtless (comparative more thoughtless, superlative most thoughtless)

Marked by or showing lack of due thought or care; careless.
Inconsiderate, inattentive.
A thoughtless remark.
Lacking thought or consideration.
The debate turned into thoughtless bickering.

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