Collocations for rigid - adj.

appear, be, seem | become, grow
He grew even more rigid and uncompromising as he got older.

extremely, very | entirely
An entirely rigid system is impractical.

excessively | fairly, rather, relatively
We operate within fairly rigid parameters.

be, feel, lie, look, stand
She feigned sleep, lying rigid in bed.

become, go | remain

very | absolutely, completely, quite | almost

with
He went absolutely rigid with shock.